HOST LISTS AND KEYS FOR EACH PLANT GENUS

(in alphabetical order)

Cra-Cyt

Cracca

Crambe

Craspedia

Crassocephalum

Crassula

Crataegomespilus

Crataegus

Craterispermum

Crateva

Cratoneurum

Cratoxylum

Crepidiastrum

Crepis

Crinodendron

Crinum

Cristaria

Critesion

Crithmum

Critonia

Crocion

Crocosmia

Crocus

Cronartium

Croomia

Crossandra

Crossopteryx

Crossostephium

Crotalaria

Croton

Cruciata

Crupina

Cryosophila

Cryptocarya

Cryptocoryne

Cryptogramma

Cryptolepis

Cryptomeria

Cryptostegia

Cryptostemma

Cryptotaenia

Cucubalis

Cucumis

Cucurbita

Cudrania

Cullen

Cuminum

Cunninghamia

Cuphea

Cupressocyparis

Cupressus

Curculigo

Curcuma

Cuscuta

Cussonia

Cutandia

Cyamopsis

Cyanotis

Cyanus

Cyathea

Cyathula

Cycas

Cyclamen

Cyclobalanopsis

Cycloloma

Cyclophorus

Cyclosorus

Cyclospermum

Cydonia

Cylactis

Cymbalaria

Cymbaria

Cymbidium

Cymbopogon

Cymboseris

Cynanchum

Cynara

Cynodon

Cynoglossum

Cynoglottis

Cynometra

Cynosurus

Cynura

Cypella

Cyperorchis

Cyperus

Cyphomandra

Cyphostemma

Cypripedium

Cyrilla

Cyrtanthus

Cyrtococcum

Cyrtomium

Cyrtopodium

Cyrtospadix

Cyrtosperma

Cystopteris

Cystostemon

Cytisophyllum

Cytisus

CraccaFabaceae
Cracca ambigua = Tephrosia florida
C. spicata = Tephrosia spicata
C. totta Aphis craccivora
CrambeBrassicaceae
Crambe abyssinica = C. hispanica ssp. abyssinica
C. cordifolia (ssp. kotschyana) Lipaphis erysimi
C. hispanica (incl. ssp. Lipaphis erysimi; Myzus persicae
abyssinica)
C. maritimaBrevicoryne brassicae;
[Lipaphis hedickei Börner 1951 – nomen nudum]
C. orientalisBrevicoryne brassicae, crambe, nigrisiphunculata
C. tataricaBrevicoryne crambe, nigrisiphunculata

Key to apterae on Crambe:-

1 ANT tubercles, and also ANT I and II, scabrous. ANT III 0.7-1.7 × SIPH, which are 1.2-2.5 × cauda…..2
ANT tubercles, ANT I and II fairly smooth. ANT III 2.5-3.7 × SIPH, which are 0.65-1.0 × cauda…..3
2 ANT tubercles low, with median tubercle developed to similar extent. SIPH 1.2-1.6 × cauda. ANT PT/BASE 1.8-2.7…..Lipaphis erysimi
ANT tubercles well developed, with inner faces convergent apically; median tubercle much lower. SIPH 1.9-2.5 × cauda. ANT PT/BASE 2.8-4.5…..Myzus persicae
3 Cauda as dark as SIPH and broadly triangular, hardly as long as its basal width in dorsal view. Paired spinal and pleural dark sclerites often present on ABD TERG 1-7. Dorsal hairs pointed…..Brevicoryne brassicae
cauda pale or dusky and tongue-shaped or elongate triangular, clearly longer than its basal width. ABD TERG 1-7 usually without dark markings (except intersegmental muscle sclerites). Dorsal hairs short and fan-shaped, or long with blunt or slightly expanded apices …..4
4 SIPH jet black, 0.65-0.8 × cauda. ANT PT/BASE 2.1-2.7. Dorsal hairs up to 2-2.5 × BD III, with blunt or slightly capitate apices…..Brevicoryne nigrisiphunculata
SIPH dark but not jet black, 0.8-1.2 × cauda. ANT PT/BASE 1.2-1.5. Dorsal hairs fan-shaped or spatulate, maximally about as long as BD III …..Brevicoryne crambe
CraspediaAsteraceae
Craspedia ?chrysantha Aphis sp. (Australia, BMNH collection)
CrassocephalumAsteraceae
Crassocephalum biafrae = Solanecio biafrae
C. bumbense = C. montuosum
C. crepidioidesAphis gossypii, spiraecola; Brachycaudus helichrysi;
[Myzus pileae]; Neomyzus circumflexus
C. guineenseAphis gossypii
C. mannii = Solanecio mannii
C. montuosumAphis fabae, gossypii, spiraecola;
Aulacorthum solani; Brachycaudus helichrysi;
Macrosiphum euphorbiae; Myzus ornatus;
Sitobion autriquei; Uroleucon compositae
C. rubensAphis fabae, gossypii, spiraecola;
Aulacorthum solani; Macrosiphum euphorbiae;
Myzus ornatus; Myzus persicae; Uroleucon compositae
C. vitellinumAphis fabae, gossypii, spiraecola;
Aulacorthum solani; Macrosiphum euphorbiae;
Myzus ornatus, persicae; Uroleucon compositae

Key to apterae on Crassocephalum:-

Dorsum with an extensive dark shield, continuous over ABD TERG 1-6. ANT III with 1-7 rhinaria. SIPH black with polygonal reticulation on distal 0.12-0.19 of length. First tarsal segments with 3-3-3 hairs…..Sitobion autriquei
Without this combination of characters…..go to key to polyphagous aphids
CrassulaCrassulaceae
Crassula coccinea Brachycaudus cardui; Neomyzus circumflexus
C. cultrataMyzus persicae
C. falcata = C. perfoliata var. falcata
C. moschataMyzus ascalonicus
C. multicavaMyzus persicae
C. perfoliata (incl. var. falcata) Aphis fabae, gossypii
C. perfossa = C. perfoliata
C. portulaceaAphis gossypii
Crassula sp.Aphis craccivora, [nerii], sedi; Myzus persicae

Key to apterae on Crassula:-

1 SIPH pale or only dark at apices …..go to key to polyphagous aphids
SIPH entirely dark…..2
2Dorsum with an extensive dark shield…..3
Dorsum without extensive dark sclerotisation…..4
3Cauda helmet-shaped. Spiracular apertures large and rounded. SIPH with a subapical annular incision…..Brachycaudus cardui
Without that combination of characters…..Aphis craccivora
4Cauda black with 11-24 hairs. Dorsal abdomen with dark cross-bands on ABD TERG 7 and 8, and some dark markings anterior to SIPH. Femora with many fine hairs longer than trochantro-femoral suture…..Aphis fabae
Cauda pale or dark with 4-8 hairs. Dorsal abdomen with or without dusky cross-bands on ABD TERG 7 and 8, usually without any dark markings anterior to SIPH. Femoral hairs all much shorter than trochantro-femoral suture…..5
5ANT PT/BASE 1.6-2.3. SIPH 0.8-1.5 × cauda, which bears 4-6 hairs and is usually rather dark, only a little paler than SIPH…..Aphis sedi
ANT PT/BASE 2.1-3.2. SIPH 1.3-2.5 × cauda, which bears 4-8 hairs and is usually pale/dusky, markedly paler than SIPH…..Aphis gossypii
×Crataegomespilus Rosaceae
×Crataegomespilus dardari Bronvaux Medlar
Dysaphis angelicae, apiifolia ssp. petroselini, lauberti,
ranunculi

Use key to aphids on Crataegus.

Crataegus Hawthorns, May Trees Rosaceae

Numerous aphids utilise species of Crataegus as their primary hosts, so that the only morphs occurring are the fundatrix and her progeny in spring (often causing leaf deformation or galling) and the return migrants and sexuales in autumn. The key that follows the host list is applicable as indicated to the spring generations of such species, but cannot be used for the autumn presexual and sexual generations. Couplets 17-27 are based on the intensive work of Stroyan (1958) and the key to Dysaphis on Crataegus by Shaposhnikov & Marolev (1978); the species-level taxonomy of the genus Dysaphis is particularly difficult, and a series of specimens from a population will need to be examined before much reliance can be placed on any species determination. This part of the key only applies to alate spring migrants, but details of the appearance of the gall and the fundatrix in life (see next section), together with the species of Crataegus colonised, may help to confirm the identification.

Host plant records for Crataegus aphids:-

Crataegus acclivis Rhopalosiphum oxyacanthae
C. alemanniensisAphis pomi; Dysaphis crataegi; Prociphilus (Stagona) pini;
Rhopalosiphum oxyacanthae
C. almaatensisAphis pomi; Ovatus insitus; Rhopalosiphum oxyacanthae
C. altaicaAphis pomi, spiraecola;
Dysaphis crataegi, crataegi ssp. pallida, lauberti,
munire, ranunculi, sorbiarum;
Ovatus crataegarius, insitus; Prociphilus (Stagona) pini;
Rhopalosiphum oxyacanthae
C. aroniaAphis gossypii, spiraecola; Ovatus crataegarius
C. azarolusAphis pomi, spiraecola;
Dysaphis apiifolia ssp. petroselini, crataegi;
Ovatus crataegarius
C. brainerdiiRhopalosiphum oxyacanthae
C. bretschneideri = C. pinnatifida ssp. major
C. calpodendronAphis pomi
C. calycinaAphis pomi; Dysaphis angelicae
C. canadensisRhopalosiphum oxyacanthae
C. carrierei = C. ×lavallei
C. champlainensis = C. submollis
C. chlorosarcaAphis pomi; Rhopalosiphum oxyacanthae
C. claraHyalomyzus eriobotryae
C. coccineaAphis pomi; Eriosoma lanigerum;
Nearctaphis crataegifoliae; Ovatus crataegarius;
Prociphilus (Neoparacletus) corrugatans;
Prociphilus (Stagona) pini; Rhopalosiphum oxyacanthae
C. columbiana auct. = C. piperi
C. crusgalliAphis fabae, pomi; Eriosoma crataegi, lanigerum;
Hyalomyzus sensoriatus; Nearctaphis clydesmithi;
Prociphilus (Neoparacletus) corrugatans;
Rhopalosiphum oxyacanthae; Utamphorophora crataegi
C. cuneataAphis spiraecola; Eriosoma lanigerum;
[Ovatus malisuctus];
Prociphilus (Stagona) crataegicola, pini;
Rhopalosiphum ?oxyacanthae, [padi]
C. curvisepalaAphis pomi; Dysaphis crataegi, incognita;
Prociphilus (Stagona) pini; Rhopalosiphum oxyacanthae
C. dahuricaAphis pomi, spiraecola
C. douglasiiAphis pomi; Dysaphis crataegi; Ericaphis gentneri;
Eriosoma lanigerum; [Myzodium mimulicola];
Nearctaphis bakeri, sclerosa;
Prociphilus (Stagona) pini
C. hissaricaAphis pomi; Dysaphis sorbiarum;
Ovatus crataegarius, insitus
C. holmesiana var. amicta Rhopalosiphum oxyacanthae
C. intricata Rhopalosiphum oxyacanthae
C. korolkowiiAphis pomi, spiraecola;
Dysaphis crataegi, crataegi ssp. pallens, incognita,
munirae
Ovatus crataegarius, insitus; Rhopalosiphum oxyacanthae
C. laevigataAphis fabae, pomi, spiraecola; Aulacorthum solani;
Dysaphis angelicae, crataegi, lauberti, ranunculi;
Ericaphis gentneri; Eriosoma lanigerum, [lanuginosum];
Macrosiphum euphorbiae; Nearctaphis crataegifoliae;
Ovatus crataegarius, insitus; Prociphilus (Stagona) pini;
Rhopalosiphum oxyacanthae
C. ×lambertianaDysaphis ranunculi; Prociphilus (Stagona) pini;
Rhopalosiphum oxyacanthae
C. ×langeiDysaphis crataegi
C. ×lavalleiEricaphis gentneri; Rhopalosiphum oxyacanthae;
Utamphorophora crataegi
C. lucidaAphis pomi
C. macrocanthaAphis pomi; Rhopalosiphum oxyacanthae
C. macrospermaAphis spiraecola
C. maximowicziiAphis pomi, spiraecola; Muscaphis stroyani;
Ovatus crataegarius, insitus, [malisuctus];
[Prociphilus kuwanai]; Rhopalosiphum oxyacanthae
C. mexicana = C. pubescens
C. mollisAphis pomi; Rhopalosiphum oxyacanthae
C. monogynaAphis fabae, gossypii, pomi, spiraecola;
Aulacorthum solani;
Dysaphis angelicae, apiifolia ssp. petroselini, [bonomii],
crataegi, lauberti, [plantaginea], ranunculi;
Macrosiphum nevskyanum;
Ovatus crataegarius, insitus; Prociphilus (Stagona) pini;
Rhopalosiphum oxyacanthae, [padi], rufulum
C. nigraAphis pomi
C. orientalisAphis pomi; Dysaphis crataegi ssp. heraclei, virgata;
Ovatus crataegarius
C. oxyacantha = C. laevigata
C. palmstruchii = C. laevigata
C. pedicellata = C. coccinea
C. pentagynaAphis pomi; Dysaphis angelicae, lauberti
C. phaenopyrumAphis pomi; Rhopalosiphum oxyacanthae
C. pinnatifida (incl. var. major) Aphis pomi, spiraecola; Muscaphis stroyani;
Ovatus crataegarius, insitus; Rhopalosiphum oxyacanthae
C. piperiEriosoma lanigerum
C. ponticaAphis pomi;
Dysaphis crataegi, crataegi ssp. pallida, munire;
Ovatus crataegarius, insitus
C. praeformosaHyalomyzus jussiaeae
C. pringleiAphis pomi
C. ×prunifoliaAphis pomi; Dysaphis crataegi;
Rhopalosiphum oxyacanthae
C. pseudoheterophylla Aphis pomi
C. pubescensMuscaphis mexicana;
Rhopalosiphum oxyacanthae, sanguinarium
C. punctataEriosoma lanigerum; Muscaphis stroyani; [Myzus ornatus];
Nearctaphis crataegifoliae
C. rivularisAphis pomi; Eriosoma lanigerum; Nearctaphis bakeri
C. rotundifoliaAphis pomi
C. sanguineaAphis pomi; Dysaphis crataegi, ranunculi; Ovatus insitus;
Prociphilus (Stagona) pini
C. ×sinaicaAphis gossypii, spiraecola; Ovatus insitus
C. songoricaAphis pomi, spiraecola;
Dysaphis crataegi ssp. pallida, munirae;
Ovatus crataegarius, insitus; Prociphilus (Stagona) pini;
Rhopalosiphum oxyacanthae
C. steveniiAphis pomi
C. submollisAphis pomi; Dysaphis crategi, ranunculi;
Prociphilus (Stagona) pini; Rhopalosiphum oxyacanthae
C. succulentaAphis pomi; Nearctaphis crataegifoliae
C. tanacetifoliaAphis pomi
C. tomentosaAphis pomi; Eriosoma crataegi;
Prociphilus (Neoparacletus) corrugatans
C. turkestanicaAphis craccivora, pomi;
Dysaphis crataegi, crataegi, ssp. pallida, munire;
Ovatus crataegarius, insitus
C. unifloraEriosoma lanigerum group; Hyalomyzus eriobotryae;
Schizoneurata tissoti; Utamphorophora crataegi
C. vicanaHyalomyzus jussiaeae
C. viridisHyalomyzus sensoriatus
Crataegus spp.[Aphis (Toxoptera) aurantii, citricidus];
Dysaphis [laserpitii], [ramani Das & Raychaudhuri 1983];
[Hyalomyzus collinsoniae]; Muscaphis canadensis;
[Myzodium mimulicola]; Nearctaphis nigrescens (?);
Prociphilus (Stagona) crataegistrobi;
Rhopalosiphum nigrum

Key to aphids on Crataegus:-

1 ANT PT/BASE less than 0.5. Antenna of alata with narrow, transversely elongate of annular secondary rhinaria…..2
ANT PT/BASE more than 0.5. Antenna of alata with oval or circular secondary rhinaria …..6
2 SIPH pores present, their rims partly sclerotised. Wax gland pore plates usually consisting of a ring of large facets around an undivided or partially divided central area (fig. 47C) …..3
SIPH absent, at least in apterae. Wax gland pore plates with numerous small facets and no central area, or with a group of large facets including a few small separate clear areas …..4
3 Aptera with greatest diameter of SIPH pore 0.08-0.16 mm. ANT III usually more than 1.25 × more than ANT IV+V…..Eriosoma crataegi
Aptera with maximum diameter of SIPH pore less than 0.06 mm. ANT III usually less than 1.25 × more than ANT IV+V…..Eriosoma lanigerum
4 Wax pore plates (in immatures) comprising groups of 6-20 large facets often including a few small clear areas. Alata (=sexupara) with media of forewing once-branched (adult aptera not known)…..Schizoneurata tissoti
Wax pore plates with more numerous small facets. Alata (= spring migrant) with media of forewing unbranched…..5
5 Fundatrix with R IV+V longer than ANT BASE V. Spring migrant alata with pterostigma of normal length, extending about one third of distance from base of Rs to tip of wing, and with 0-4 rhinaria on ANT V…..Prociphilus (Neoparacletus) corrugatans
Fundatrix with R IV+V shorter than ANT BASE V. Spring migrant alata with pterostigma elongate distally, extending about one half of distance from base of Rs to tip of wing, and with 3-11 rhinaria on ANT V…..Prociphilus (Stagona) spp. (crataegicola, crataegistrobi, pini)
6 Cauda usually short, helmet-shaped or triangular, shorter than or about as long as its basal width in dorsal view; if tongue-shaped and up to 1.4 × its basal width then SIPH have rows of minute nodules or spinules on closely-spaced imbrications…..7
Cauda tongue- or finger-shaped, clearly longer than its basal width; sometimes less than 1.4 × longer, but then SIPH do not have closely-spaced rows of minute nodules/spinules…..28
7 Dorsal cuticle of aptera (fundatrix) very rough with numerous small denticulate or wart-like projections, and clothed with numerous long, fine, curved hairs mostly over 60 µm long (fig. 42A). Alata without a solid black dorsal abdominal patch, and with SIPH more than 2 × cauda…..8
Dorsal cuticle of aptera (fundatrix or subsequent generation) smooth, with fewer, shorter hairs (maximally 50 µm). Alata usually with a solid black dorsal abdominal patch, or if without then SIPH less than 2 × cauda…..10
8 SIPH of aptera (fundatrix) 0.25-0.28 mm long, 1.6-2.0 × ANT V BASE. Alata with 12-22 secondary rhinaria on ANT III, 6-11 on IV, 2-5 on V, and ANT PT/BASE 1.7-2.6 …..Muscaphis mexicana
SIPH of fundatrix 0.33-0.45 mm long, 2.2-3.0 × than ANT V BASE. Alata with 25-50 secondary rhinaria on ANT III, 15-33 on IV, 9-20 on V, and ANT PT/BASE 3.0-4.5 …..9
9 Cauda of fundatrix bluntly triangular (fig. 42B). SIPH of fundatrix 4-5 × its minimum width, and that of alata 5-6 × its minimum width…..Muscaphis canadensis
Cauda of fundatrix helmet-shaped, with a pointed apex (fig. 42C). SIPH of fundatrix 7-8 × its minimum width, and of that of alata 6.5-8.5 × its minimum width …..Muscaphis stroyani
10SIPH with closely-spaced rows of imbrications bearing numerous small nodules or spinules (fig. 42M) …..11
SIPH normally imbricated, the imbrications sometimes spinulose but not in regular closely-spaced rows…..16
11Dorsum of aptera with a solid black central sclerite covering ABD TERG 3-5, or 3-6, and transverse bars on more posterior tergites…..12
Dorsum of aptera with separate transverse bars on ABD TERG 5-8, and with irregular broken sclerites on more anterior tergites…..14
12Tibiae black. Aptera with dorsal patch extending laterally to marginal sclerites, at least on ABD TERG 4-5…..Nearctaphis clydesmithi
Tibiae mainly pale with black apices. Aptera with dorsal patch not extending laterally to marginal sclerites…..13
13Alata with a solid black patch on ABD TERG 3-5, partially fused with bar on 6 …..Nearctaphis nigrescens
Alata without a solid black dorsal patch, only with transverse bars or dashes on ABD TERG 5-8…..Nearctaphis sclerosa
14R IV+V 0.14-0.18 mm long, usually with 4 accessory hairs. Alata without a solid black dorsal abdominal patch…..15
R IV+V 0.10-0.13 mm long, usually with 2 accessory hairs. Alata with a solid black patch covering ABD TERG 3-5, or 3-6…..Nearctaphis bakeri
15Head of aptera blackish-brown, and SIPH darker than cauda. Alata has transverse dark bars on ABD TERG 6-8, or 7 and 8…..Nearctaphis crataegifoliae ssp. occidentalis
Head of aptera pale, and SIPH paler than cauda. Alata with a complete transverse dark bar only on ABD TERG 8…..Nearctaphis crataegifoliae ssp. crataegifoliae
16Spinal tubercles usually present and well developed on head, prothorax and all abdominal segments. SIPH of aptera pale or dusky, less than 0.14 mm long …..Dysaphis sorbiarum
Spinal tubercles only on head and ABD TERG 7-8, rarely on other segments. SIPH dark, more than 0.14 mm long…..17
17Spring migrant alata (henceforth “s.m.a.”) with marginal tubercles present on ABD TERG 7 in most specimens, frequently on both sides. Hairs on ABD TERG 8 usually 10-25 µm long…..Dysaphis apiifolia ssp. petroselini
S.m.a. without marginal tubercles on ABD TERG 7 in most specimens, and very rarely on both sides. Hairs on ABD TERG 8 30-70 µm long…..18
18S.m.a. with total number of secondary rhinaria on both ANT V combined 7-35, or if 5-6 then a transverse dark bar is present on ABD TERG 2…..19
S.m.a. with usually only 0-5 secondary rhinaria on both ANT V combined, rarely up to 6 or 7. ABD TERG 2 without a dark bar…..21
19ABD TERG 1 and 2 of s.m.a. without dark bars, at most they have small scattered circular scleroites…..Dysaphis angelicae
ABD TERG 2, or both 1 and 2, of s.m.a. with a transverse dark bar, sometimes partly broken into irregular sclerites…..20
20ANT III of s.m.a. with 44-75 secondary rhinaria, ANT IV with 15-35 and ANT V with 3-19. R IV+V with 4-7 accessory hairs…..Dysaphis ranunculi
ANT III of s.m.a. with 37-47 secondary rhinaria, ANT IV with 10-19 and ANT V with 2-6. R IV+V with 2-3 accessory hairs…..Dysaphis virgata
21ANT III of s.m.a. usually with 74-125 secondary rhinaria per mm of length …..22
ANT III of s.m.a. usually with 130-192 secondary rhinaria per mm of length …..24
22HT I of s.m.a. with 3 hairs (medial sense peg present). R IV+V with 5-9 accessory hairs …..Dysaphis munire
HT I of s.m.a. with 2 hairs (medial sense peg absent). R IV+V usually with 2-4 accessory hairs…..23
23R IV+V of s.m.a. 1.01-1.25 × HT II. Hairs on ANT III blunt or weakly capitate, 9-21 µm long, those on ABD TERG 3 12-23 µm long…..Dysaphis incognita
R IV+V of s.m.a. 0.83-0.98 × HT II. Hairs on ANT III mostly pointed, 20-29 µm long, those on ABD TERG 3 25-35 µm long…..Dysaphis crataegi ssp. pallida
24S.m.a. with hairs on ABD TERG 2 and 3 pointed, the longest 20-57 µm long, but rarely less than 25 µm…..Dysaphis lauberti
S.m.a. with hairs on ABD TERG 2 and 3 blunt, the longest 9-29 µm, but rarely more than 25 µm…..25
25S.m.a. with SIPH 2.9-3.5 × their middle diameter …..Dysaphis crataegi ssp. heraclei
S.m.a. with SIPH 3.6-5.7 × their middle diameter…..26
26S.m.a. with dorsal abdominal patch on ABD TERG 3-6 interrupted by narrow gaps or lacunae between 3-4 and 4-5, as well as 5-6 (fig. 42F). Anterior part of subgenital plate with 4-10 hairs…..Dysaphis crataegi ssp. kunzei
S.m.a. with dorsal abdominal patch on ABD TERG 3-6 almost entire, except for a narrow central gap between 5 and 6 (fig. 42G). Anterior part of subgenital plate with 2-7 hairs …..27
27(Requires large samples) Most s.m.a. with at least 1 antenna bearing 1 (or more) secondary rhinaria on ANT V [mean number per antenna 0.53 (UK) – 1.1 (Russia)] …..Dysaphis crataegi s. str.
Most s.m.a. without any secondary rhinaria on ANT V of either antenna [mean number 0.32 per antenna (UK)] …..Dysaphis crataegi ssp. aethusi
28Antennal tubercles undeveloped or weakly developed. SIPH of aptera dark or, if only dark at apex, then short (less than 0.25 mm). Cauda and anal plate dusky to dark …..29
Antennal tubercles moderately to well developed. SIPH of aptera pale or dusky, or dark only at apices and then over 0.3 mm long…..35
29 SIPH slightly swollen or cylindrical on at least basal 0.7 of length, narrowing only towards apex, and with a well-developed apical flange (e.g. fig. 42L). Marginal tubercles on ABD TERG 7 placed posteriodorsad of spiracle, and usually smaller at base than the spiracular opening (fig. 42H)…..30
SIPH tapering from base to apex, and flange only moderately developed. Marginal tubercles on ABD TERG 7 placed posterioventrad of spiracle and usually larger than spiracular aperture…..32
30Tibiae wholly dark…..Rhopalosiphum nigrum
Tibiae mainly pale or dusky, sometimes dark at apices…..31
31ANT PT/BASE less than 2.0 in fundatrix, and less than 2.5 in subsequent generations (apterae and spring migrant alatae). SIPH of alata usually less than 0.2 mm long (fig. 42L) …..Rhopalosiphum rufulum
ANT PT/BASE more than 2.0 in fundatrix, and more than 2.5 in subsequent generations. SIPH of alata usually more than 0.2 mm long…..Rhopalosiphum oxyacanthae (or sanguinarium – see text)
32Aptera with transverse bars on ABD TERG 7 and 8 and at least some dark spino-pleural markings anterior to siphunculi. Alata with a series of dorsal abdominal transverse bars …..Aphis fabae
Aptera without any dark dorsal markings, alata usually with only marginal abdominal sclerites anterior to siphunculi…..32
33Cauda of aptera paler than SIPH, without any trace of a constriction, and bearing 4-8 hairs (fig. 121U) …..Aphis gossypii
Cauda of aptera as dark as SIPH, with a slight constriction near its midpoint, and bearing 7-19 hairs (fig. 121T) …..34
34Marginal tubercles present on ABD TERG 2-4. Cauda with 10-19 hairs (rarely less than 13).R IV+V more than 0.130 mm…..Aphis pomi
Marginal tubercles absent from ABD TERG 2-4. Cauda with 7-15 hairs (rarely more than 12). R IV+V less than 0.125 mm…..Aphis spiraecola
35Aptera with inner faces of antennal tubercles convergent in dorsal view (e.g. fig. 42I) …..36
Aptera with inner faces of antennal tubercles parallel or divergent in dorsal view (e.g. figs 42J, K) …..41
36SIPH slightly to moderately swollen over distal 0.5 to 0.7 of length. ANT PT/BASE less than 5…..37
SIPH tapering gradually from base to flange. ANT PT/BASE more than 5 …..40
37ANT PT/BASE 2.5 or less…..Hyalomyzus sensoriatus
ANT PT/BASE more than 3.0…..38
38R IV+V less than 1.1 × HT II. Cauda with 6-11 hairs (usually 7). Alata with a black dorsal abdominal patch…..Myzus persicae
R IV+V more than 1.1 × HT II. Cauda with 4-6 hairs. Alata without a black dorsal abdominal patch….. 39
39SIPH of aptera moderately swollen, and only moderately imbricated (fig. 42N). ANT PT less than 1.1 × ANT III. Alata with 40 or more secondary rhinaria on ANT III …..Hyalomyzus eriobotryae
SIPH of aptera only slightly swollen, and coarsely imbricated (fig. 42O, as tissoti). ANT PT more than 1.2 × ANT III. Alata with 11-25 (-39) secondary rhinaria on ANT III …..Hyalomyzus jussiaeae
40Spring migrant alata with 60-83 secondary rhinaria on ANT III, 36-52 on IV and 13-22 on V…..Ovatus insitus
Spring migrant alata with 22-49 rhinaria on ANT III, 5-20 on IV and 0-10 on V …..Ovatus crategarius
41SIPH with a subapical zone of polygonal reticulation (fig. 121C). Longest hairs on ANT III more than 0.5 × basal diameter of segment…..42
SIPH without any polygonal reticulation. Hairs on ANT III all less than 0.5 × basal diameter of segment…..43
42Alata with ANT c.1.75 × BL, and with ANT III bearing 30-34 rhinaria. (Aptera are undescribed)…..Macrosiphum nevskyanum*
Alata with ANT less than 1.5 × BL, and ANT III with 12-21 rhinaria …..Macrosiphum euphorbiae
43SIPH swollen on about distal 0.5 of length (fig. 42P). Alata without dark dorsal abdominal markings…..Utamphorophora crataegi
SIPH tapering, cylindrical or only slightly swollen subapically (e.g. fig. 42Q). Alata with dark dorsal abdominal markings…..44
44SIPH more than 2 × cauda, and in aptera often dark-tipped (fig. 121K). Dorsal abdomen of alata with transverse dark bars…..Aulacorthum solani
SIPH less than 2 × cauda, not dark-tipped in aptera (fig. 42Q). Dorsal abdomen of alata with an almost solid dark patch across ABD TERG 4-5 or 3-5 …..Ericaphis gentneri
Craterispermum Rubiaceae
Craterispermum laurinum Aphis gossypii; Myzus persicae; Sitobion sp
Crateva Capparaceae
Crateva religiosaBrachycaudus helichrysi; Myzus persicae

Use key to polyphagous aphids.

CratoneurumAmblystegiaceae
Cratoneurum filicinum Muscaphis utahensis; Pemphigus hydrophilus

Use key to apterae of moss-feeding aphids under Polytrichum.

Cratoxylum Hypericaceae
Cratoxylum celebicum Greenideoidea (Neogreenideoida) philippensis
C. cochinchinense Aphis aurantii, gossypii
C. polyanthum = C. cochinchinense

Key to species:-

Body elongate. SIPH almost as long as body with numerous long hairs ….. Greenideoidea (Neogreenideoida) philippensis
Body oval. SIPH shorter and without hairs …..go to key to polyphagous aphids
CrepidiastrumAsteraceae
Crepidiastrum lanceolatum Myzus lactucicola
C. sonchifoliumUroleucon formosanum

Use key to apterae on Ixeris.

CrepisAsteraceae
Crepis alpestrisUroleucon cichorii, hypochoeridis
C. asperaUroleucon picridis
C. atribarbaUroleucon erigeronense
C. aureaNasonovia ribisnigri
C. biennisAphis crepidis, fabae; Aulacorthum palustre, solani;
Brachycaudus helichrysi; Hyperomyzus picridis;
Myzus ascalonicus; Nasonovia ribisnigri;
Pemphigus bursarius; Trama troglodytes;
Uroleucon cichorii, grossum
C. blattarioides = C.pyrenaica
C. bursifoliaAphis crepidis
C. capillaris (incl. virens) Aphis crepidis, fabae, nasturtii; Brachycaudus cardui;
Hyperomyzus lactucae; Macrosiphum euphorbiae;
Myzus ornatus;
Nasonovia [compositellae ssp. nigra], ribisnigri;
Pemphigus bursarius;
Trama maritima, [mordvilkoi], troglodytes;
Uroleucon cichorii, grossum, murale, sonchi
C. conyzifoliaAphis fabae; Brachycaudus cardui; Nasonovia ribisnigri;
Uroleucon cichorii, grossum
C. foetida (incl. ssp. rhoeadifolia)Aphis (Protaphis) sp.; Uroleucon cichorii
C. grandiflora = C. conyzifolia
C. haenseleri = C. vesicaria ssp. taraxacifolia
C. hieracioides = C. mollis ssp. succisiifolia
C. japonica = Youngia japonica
C. leontodontoides Uroleucon grossum
C. marschalliiUroleucon picridis
C. mollis ssp. succisiifolia Uroleucon grossum
C. multicaulisUroleucon grossum
C. neglectaNasonovia ribisnigri; Uroleucon picridis
C. nicaeensisUroleucon cichorii
C. palaestina Nasonovia ribisnigri
C. paludosaHyperomyzus picridis; [Jacksonia papillata];
Nasonovia ribisnigri;
Uroleucon cichorii, grossum, riparium
C. parviflora[Uroleucon picridis (misidentified cichorii?)]
C. praemorsaAphis fabae, nasturtii; Myzus ornatus;
Nasonovia ribisnigri; Uroleucon cichorii, grossum
C. pulchraNasonovia ribisnigri; Uroleucon sonchi
C. pyrenaicaUroleucon cichorii
C. rhoeadifolia = C. foetida ssp. rhoeadifolia
C. sanctaAphis crepidis; Uroleucon sonchi
C. sancta ssp. obovata Uroleucon cichorii
C. setosaHyperomyzus picridis; Macrosiphum euphorbiae;
Uroleucon cichorii, [cirsii], grossum
C. sibiricaAphis fabae; [Cryptomyzus ribis]; Hyperomyzus picridis;
Pemphigus bursarius;
Uroleucon cichorii, grossum, picridis
C. taraxacifolia = C. vesicaria ssp. taraxacifolia
C. tectorumAphis crepidis, seneciocrepiphaga;
Aulacorthum solani; Hyperomyzus lactucae, sandilandica;
Macrosiphoniella crepidis; Nasonovia ribisnigri;
Trama troglodytes;
Uroleucon cichorii, grossum, riparium, sonchi
C. tenuifoliaAcyrthosiphon crepidis; Macrosiphoniella crepidis
C. triasiiBrachycaudus cardui, helichrysi; Hyperomyzus lactucae
C. vesicariaAphis crepidis, gossypii, [intybi]; Aulacorthum solani;
(incl. haenseleri, Hyperomyzus lactucae; Myzus ornatus, persicae;
taraxacifolia) Nasonovia ribisnigri;
Uroleucon cichorii, grossum, sonchi
C. virens = C. capillaris
C. viscidulaNasonovia ribisnigri
Crepis spp.[Aphis septentrionalis];
Uroleucon adenocaulonae, [sileneobium]

Key to apterae on Crepis:-

1 ANT PT/BASE less than 0.5…..2
ANT PT/BASE more than 1…..4
2 HT II normal. Body sparsely hairy. Wax glands present on posterior abdomen …..Pemphigus bursarius
HT II very elongate. Body densely hairy. No wax glands…..3
3 Eyes with 3 facets. SIPH absent…..Trama troglodytes
Eyes with many facets. SIPH present as pores on shallow cones …..Trama maritima
4SIPH with a distal zone of polygonal reticulation (at least 4 rows of polygonal cells) …..5
SIPH without polygonal reticulation…..16
5SIPH pale, with reticulation consisting of large cells on distal 0.08-0.2 of length. First tarsal segments with 3-3-3 hairs…..Macrosiphum euphorbiae
SIPH wholly or mainly dark, with reticulation of numerous small cells on distal 0.16-0.55 of length. First tarsal segments with 3-3-3 or 5-5-5 hairs…..6
6Cauda dark…..7
Cauda pale…..8
7SIPH 0.9-1.2 × cauda with reticulation on distal 0.45-0.55. R IV+V 0.6-0.7 × HT II. First tarsal segments with 3-3-3 hairs…..Macrosiphoniella crepidis
SIPH 1.5-2.1 × cauda with distal 0.16-0.23 reticulated. R IV+V 1.1-1.2 × HT II. First tarsal segments with 5-5-5 hairs…..Uroleucon riparium
8Crescent-shaped antesiphuncular sclerites present (sometimes subdivided) …..9
Antesiphuncular sclerites absent…..11
9 R IV+V 1.45-1.85 × HT II. Coxae pale like basal parts of femora …..Uroleucon picridis
R IV+V 0.84-1.35 × HT II. Coxae dusky or dark, darker than the basal parts of femora …..10
10R IV+V 0.84-1.08 × HT II (rarely more than 1). Cauda with 14-24 hairs (usually about 17) …..Uroleucon hypochoeridis
R IV+V 1.04-1.35 × HT II. Cauda with 18-33 hairs …..Uroleucon cichorii group (incl. grossum)
11SIPH with pale basal part contrasting with dark distal part …..Uroleucon erigeronense
SIPH entirely dark or only paler in middle…..12
12Coxae dark. SIPH often slightly paler in middle. Dorsal hairs not arising from pigmented scleroites …..Uroleucon sonchi
Coxae pale. SIPH wholly dark. Dorsal hairs with or without pigmented scleroites at bases …..13
13ANT III with rhinaria distributed over at least 0.9 of length. R IV+V 0.8-1.0 × HT II …..Uroleucon murale
ANT III with rhinaria on basal 0.5-0.7. R IV+V 1.05-2.2 × HT II…..14
14SIPH 1.7-2.1 × cauda. R IV+V 1.9-2.2 × HT II …..Uroleucon adenocaulonae
SIPH 1.1-1.5 × cauda. R IV+V 0.9-1.45 × HT II…..15
15HT II rather long and thin, 6 or more × longer than its maximum thickness and 0.9-1.1 × R IV+V…..Uroleucon pseudambrosiae
HT II less than 5 × its maximum thickness and 0.70-0.85 × R IV+V …..Uroleucon ambrosiae
16 Cauda helmet-shaped, shorter than its basal width. SIPH conical or tapering, with a subapical annular incision …..17
Cauda tongue-shaped or triangular, longer than its basal width. SIPH varying, if tapering then without a subapical annular incision…..18
17Dorsal abdomen with an extensive solid black shield. ANT III 0.31-0.47 mm, 2.4-3.4 × HT II. R IV+V 0.17-0.24 mm. SIPH dark, imbricated, 1.7-3.4 × cauda ……Brachycaudus cardui
Dorsal abdomen without a black shield. ANT III 0.07-0.25 mm, 0.9-2.2 × HT II. R IV+V 0.10-0.15 mm. SIPH pale, smooth, 0.8-2.0 × cauda ……Brachycaudus helichrysi
18Head spiculose both dorsally and ventrally, with spiculose or scabrous, almost parallel or apically convergent ANT tubercles…..go to key to polyphagous aphids, starting at couplet 5
Head not spiculose, or only spiculose on ventral side. ANT tubercles undeveloped, or if developed then with inner faces almost smooth, and divergent…..19
19ANT III with 1-40 rhinaria; if a small number then they are on basal half only. ANT tubercles moderately to well developed, projecting beyond middle of front of head in dorsal view. ABD TERG 1 and 7 without marginal tubercles (MTu)…..20
ANT III usually without rhinaria, if with 0-4 then these are distributed over its length. ANT tubercles undeveloped or weakly developed. ABD TERG 1 and 7 always with MTu …..25
20SIPH clavate, swollen to at least 1.2 of minimum diameter on basal half …..21
SIPH tapering, cylindrical or only slightly swollen towards apex…..23
21SIPH pale. R IV+V 0.8-1.0 × HT II. (Al. with a dark trapezoid dorsal abdominal patch) …..Hyperomyzus lactucae
SIPH dusky or dark at least on distal part. R IV+V 1.05-1.7 × HT II. (Al. without a dark dorsal abdominal patch)…..22
22R IV+V 1.05-1.25 × HT II. SIPH lightly imbricated, 2.0-2.4 × cauda, with maximum diameter of swollen part 1.3-1.5 × minimum diameter on basal half …..Hyperomyzus sandilandica
R IV+V 1.5-1.7 × HT II. SIPH smooth, 1.5-1.65 × cauda, with maximum width of swollen part 1.5-2.0 × minimum width on basal half…..Hyperomyzus picridis
23 Thoracic spiracular apertures large and rounded, much larger than abdominal ones. Dorsal abdomen with dark intersegmental markings. Hairs on ANT III up to 0.7-1.1 × BD III …..Nasonovia ribisnigri
Thoracic spiracular apertures not unusually large. Dorsal abdomen without dark intersegmental markings. Hairs on ANT III very short, maximally c.0.25 × BD III …..24
24R IV+V 0.6-0.7 × HT II. SIPH 1.15-1.45 × cauda …..Acyrthosiphon crepidis*
R IV+V 1.2-1.3 × HT II. SIPH 1.8-2.5 × cauda…..Aulacorthum palustre
25ANT PT/BASE c. 1.0 or less…..Aphis (Protaphis) sp.
ANT PT/BASE 1.7-3.9…..26
26 Tibiae entirely dark. Hairs on ANT III 1.7-3.3 × BD III …..Aphis seneciocrepiphaga*
Tibiae dark only distally. Hairs on ANT III 0.3-1.7 × BD III…..27
27Most or all of ABD TERG 2-5 usually with dome-shaped MTu. Posterior hair on hind trochanter blunt, 0.3-0.5 × diameter of trochantro-femoral suture. Longest hair on ANT III 0.25-0.55 × BD III. ANT III sometimes with up to 6 secondary rhinaria …..Aphis crepidis
ABD TERG 2-5 rarely with MTu. Posterior hair on hind trochanter pointed, 0.55-1.54 × diameter of trochantro-femoral suture. Longest hair on ANT III 0.47-0.8 × BD III. ANT III without secondary rhinaria (except in alatiform specimens) …..go to key to polyphagous aphids, starting at couplet 24
CrescentiaBignoniaceae
Crescentia cujeteAphis (Toxoptera) citricidus
CrinodendronElaeocarpaceae
Crinodendron patagua Myzus ornatus; Neomyzus circumflexus

Use key to polyphagous aphids.

CrinumAmaryllidaceae
Crinum careyanum = C. zeylanicum
C. zeylanicumAphis gossypii
Cristaria see GayaMalvaceae
Cristaria corchorifolia = Gaya parviflora
Critesion see HordeumPoaceae
CrithmumApiaceae
Crithmum maritimum Aphis fabae; Cavariella aegopodii; Dysaphis crithmi;
Hyadaphis foeniculi;
Macrosiphum ?centranthi – (Ilharco 1984)
[Uroleucon cichorii]

Key to apterae on Crithmum:-

1 ANT tubercles well developed, smooth, divergent. SIPH elongate (0.3-0.45 × BL), with a distal zone of polygonal reticulation…..Macrosiphum ?centranthi
ANT tubercles absent or weakly developed. SIPH relatively shorter and without polygonal reticulation…..2
2ABD TERG 8 with a backward-pointing process above cauda. ANT PT/BASE 0.64-1.25 …..Cavariella aegopodii
No supracaudal process. ANT PT/BASE 1.2-4.0…..3
3Cauda helmet-shaped, not longer than its basal width in dorsal view, with 4-5 hairs. Head and ABD TERG 7 and 8 usually with spinal tubercles (STu) …..Dysaphis crithmi
Cauda finger-like, much longer than its basal width., with 6-25 hairs. No STu …..4
4SIPH cylindrical or tapering. ABD TERG 1 and 7 with marginal tubercles (MTu). Cauda with 11-25 hairs…..Aphis fabae
SIPH clavate. MTu usually present on ABD TERG 5, but absent from 1 and 7. Cauda with 6-9 hairs…..Hyadaphis foeniculi
CritoniaAsteraceae
Critonia portoricensis Uroleucon ambrosiae
Crocion see ViolaViolaceae
Crocion nutallii see Viola nutallii
CrocosmiaIridaceae
Crocosmia ×crocosmiiflora Aphis fabae
CrocusIridaceae
Crocus atticus = C. sieberi ssp. atticus
C. “carduchorum” = C. kotschyanus
C. kotschyanusDysaphis tulipae
C. sativusAulacorthum solani; Myzus ascalonicus
C. sieberi ssp. atticus Myzus persicae
Crocus spp. Aphis gossypii; [Idiopterus nephrelepidis];
Neomyzus circumflexus;
Rhopalosiphoninus latysiphon, staphyleae

Key to apterae on Crocus:-

Cauda helmet-shaped, not longer than its basal width in dorsal view. Spinal tubercles (STu) usually present, at least on head and ABD TERG 8…..Dysaphis tulipae
Cauda tongue-shaped, clearly longer than its basal width. STu rarely present, and never on head..…go to key to polyphagous aphids
CronartiumMycetales
Cronartium fusiforme Cinara cronartii (in lesions of Pinus)
CroomiaStemonaceae
Croomia heterosepala Aphis spiraecola
C. japonicaAphis spiraecola
CrossandraAcanthaceae
Crossandra infundibuliformis Aphis gossypii; Myzus persicae; Neomyzus circumflexus
C. pungensMyzus persicae

Use key to polyphagous aphids.

Crossopteryx Rubiaceae
Crossopteryx febrifuga Aphis gossypii; Sitobion halli
Crossostephium see LepidolopsisAsteraceae
CrotalariaFabaceae
Crotalaria alataAphis gossypii
C. anagyroides = C. micans
C. atrorubensAphis gossypii
C. barkaeAphis gossypii
C. brownei = C. pallida
C. capensisAcyrthosiphon pisum
C. comosaAphis gossypii
C. glaucaAphis gossypii
C. goreensisAphis craccivora, gossypii
C. hyssopifoliaAphis gossypii
C. junceaAphis craccivora, gossypii; Pseudomegoura magnoliae
C. laburnifoliaMyzus persicae
C. lanceolataAphis craccivora
C. longirostrataAphis craccivora
C. madurensisAphis (Toxoptera) aurantii
C. mesoponticaAphis craccivora
C. micans Brachycaudus helichrysi
C. mucronata = C. pallida
C. naragutensisAphis gossypii
C. ochroleucaAphis craccivora, gossypii
C. pallida Aphis craccivora, fabae, gossypii;
Brachycaudus helichrysi; [Schizaphis rotundiventris]
C. reptansAphis craccivora
C. retusaAphis gossypii
C. rogersiiAphis craccivora
C. saltianaAphis craccivora, gossypii, spiraecola;
Brachycaudus helichrysi
C. spectabilisAphis craccivora
C. stipulariaMacrosiphum euphorbiae
C. striata = C. pallida
Crotolaria spp.Aphis nasturtii; Myzus ornatus;
Sitobion nigrinectarium

Key to apterae on Crotalaria:-

1SIPH black with a distal zone of polygonal reticulation …..Sitobion nigrinectarium
SIPH pale or dark, if dark then without polygonal reticulation…..2
2ANT VI BASE 0.25-0.4 mm, 1.8-2.3 × R IV+V. SIPH very attenuate distally, with minimum diameter less than 0.25 × width of cauda at midlength in dorsal view …..Acyrthosiphon pisum
ANT VI BASE less than 0.2mm, less than 1.5 × R IV+V. SIPH clavate, cylindrical or tapering but not attenuate and of diameter more than 0.3 × width of cauda at midlength …..go to key to polyphagous aphids
CrotonEuphorbiaceae
Croton bonplandianus Myzus persicae
C. congestus = Xylosma congesta
C. floribundusAphis (Toxoptera) citricidus
C. humilisAphis spiraecola
C. lobatusAphis craccivora, gossypii
C. macrostachysEonaphis crotonis; Myzus persicae
C. subgratissimus Eonaphis crotonis
C. tigliumAphis (Toxoptera) aurantii
Croton spp.Brachycaudus helichrysi; Sinomegoura citricola

Key to species on Croton:-

Aptera and alata with very large spine-like processes, 4 per segment, longer than the short, black, conical SIPH which have a subapical ring of 4 hairs (fig. 43)…..Eonaphis crotonis
Aptera and alata without spine-like processes. SIPH tubular or tapering, longer than basal width, without hairs…..go to key to polyphagous aphids
CruciataRubiaceae
Cruciata glabraMyzus cerasi; Uhlmannia singularis
C. laevipesAphis galiiscabri; Myzus cerasi
C. tauricaAphis nonveilleri; Dysaphis reaumuri
Use key to apterae on Galium.
CrupinaAsteraceae
Crupina vulgarisAphis fabae; Macrosiphoniella papillata
Crupina sp.Macrosiphoniella riedeli

Key to apterae on Crupina:-

1SIPH thick and dark with distal polygonal reticulation, a very long pointed cauda, R IV+V about equal to HT II, and dorsal hairs arising from tuberculate bases…..2
Without that combination of characters…..Aphis fabae
(or use key to polyphagous aphids)
2ANT and legs almost wholly jet black, except for base of ANT III and basal 0.1-0.2 of femora. ANT III with 20-34 rhinaria…..Macrosiphoniella papillata
ANT and legs are mainly dark, but basal parts of ANT IV and V are paler, as well as base of III, tibiae are usually paler in middle, and femora are pale on basal 0.4-0.6. ANT III with 34-51 rhinaria…..Macrosiphoniella riedeli
Cryosophila Arecaceae
Cryosophila warscewiczii Cerataphis brasiliensis

Use key to apterae on palms under Calamus.

Cryptocarya Lauraceae
Cryptocarya albaAphis sp. near martinae (BMNH collection, Chile)
CryptocoryneAraceae
Cryptocoryne ciliata Rhopalosiphum nymphaeae
CryptogrammaPteridaceae
C. crispaMacrosiphum woodsiae
Cryptogramma sp. (?) Macrosiphum clydesmithi

Use key to fern-feeding aphids under Polypodium.

CryptolepisApocynaceae
Cryptolepis transvaalensis Aphis gossypii
Cryptomeria Taxodiaceae
Cryptomeria japonica [Brachycaudus helichrysi];
Cinara fresai, [greeni (Schouteden 1905)]
CryptostegiaApocynaceae
C. grandifloraAphis asclepiadis, aurantii, craccivora, gossypii, nerii,
spiraecola
C. madagascariensis Aphis craccivora, gossypii, nerii, spiraecola

Use key to aphids on Asclepias.

Cryptostemma see ArctothecaAsteraceae
CryptotaeniaApiaceae
Cryptotaenia africana Aphis gossypii; Macrosiphum euphorbiae
C. canadensisAphis asclepiadis, gossypii, spiraecola;
Aulacorthum solani;
Cavariella aegopodii, japonica, oenanthi, salicicola;
Hyadaphis foeniculi; Macrosiphum euphorbiae;
Neomyzus circumflexus; [Pemphigus sp.];
Semiaphis heraclei
C. japonicaAphis gossypii, [mitsubae Shinji ( = spiraecola?)],
spiraecola;
Aulacorthum solani;
Cavariella japonica, oenanthi, salicicola;
Amphorophora cryptotaeniae; Myzus persicae;
Semiaphis heraclei

Key to apterae on Cryptotaenia:-

1ABD TERG 8 with a posteriorly projecting process above cauda; in some species this is reduced to a small, warty, knob in the centre of ABD TERG 8, with 2 associated hairs …..2
No supracaudal process, nor are there are 2 hairs on ABD TERG 8 close together and associated with a warty knob…..5
2SIPH clavate; swollen on distal half to at least 1.2 × narrowest part of basal half …..3
SIPH tapering or cylindrical, or with slight subapical swelling…..4
3Supracaudal process longer than (1.2-1.5 ×) cauda. SIPH coarsely imbricated and stout, less than 5 × longer than the maximum width of the swollen part …..Cavariella salicicola
Supracaudal process almost always shorter than (0.75-1.05 × cauda. SIPH weakly imbricated and more than 5 × longer than maximum width of swollen part …..Cavariella aegopodii
4Femoral hairs numerous, long and fine, longer than 0.5 × width of hind femur …..Cavariella oenanthi
Femoral hairs sparse, short and rigid, shorter than 0.5 × width of hind femur …..Cavariella japonica
5SIPH very small and flangeless; less than 0.5 × cauda and often not much longer (1.0-1.8 ×) than their diameter at midlength…..Semiaphis heraclei
SIPH more than 0.6 × cauda, and with a flange…..6
6SIPH tapering or cylindrical..…go to key to polyphagous aphids
SIPH swollen or clavate…..7
7Head smooth or slightly rugose with ANT tubercles undeveloped. ANT PT/BASE 1.2-3.0. R IV+V 0.7-1.05 × HT II. SIPH dark (or pale in summer dwarfs), and 0.9-1.4 × cauda …..Hyadaphis foeniculi
Head spiculose with ANT tubercles well developed. ANT PT/BASE 2.8-5.1. R IV+V 0.9-1.7 × HT II. SIPH pale and 1.7-3.0 × cauda…..8
8SIPH strongly clavate, with swollen part maximally 1.8-2.1 × minimum width on basal part, and with a subapical constriction bearing 2-3 rows of tranverse striae below the well-developed flange. R IV+V 1.5-1.7 × HT II. Apex of ANT PT pointed …..Amphorophora cryptotaeniae
SIPH slightly clavate, with swollen part less than 1.5 × minimum width of basal part, and without a distinct subapical constriction. R IV+V 0.9-1.2 × HT II. Apex of ANT PT not fine-pointed…..Myzus persicae
CucubalusCaryophyllaceae
Cucubalus baccifer = Silene baccifera
CucumisCucurbitaceae
Cucumis anguriaAphis gossypii
C. dipsaceusProtaphis middletonii
C. ficifoliusAphis gossypii
C. figarei = C. ficifolius
C. hirsutusAphis gossypii
C. melo[Acyrthosiphon cyparissiae];
Aphis craccivora, fabae, gossypii;
Aulacorthum solani; [Brevicoryne brassicae];
[Cavariella salicicola]; [Macrosiphoniella sanborni];
Macrosiphum euphorbiae; Myzus persicae;
Pseudomegoura magnoliae
C. moschatus = C. melo
C. myriocarpusAphis gossypii
C. sativus[Acyrthosiphon cyparissiae];
Aphis craccivora, fabae, frangulae, gossypii, spiraecola;
Aulacorthum solani, spinacaudatum;
Brachycaudus helichrysi; [Lipaphis pseudobrassicae];
Macrosiphum euphorbiae; Myzus ornatus, persicae;
Neomyzus circumflexus; Protaphis middletonii;
Pseudomegoura magnoliae; Rhopalosiphoninus latysiphon;
[Rhopalospihum rufiabdominale]; Sinomegoura citricola

Use key to apterae on Cucurbita.

CucurbitaCucurbitaceae
Cucurbita ficifolia Aphis craccivora, fabae, gossypii; Aulacorthum solani;
Macrosiphum euphorbiae; Myzus persicae
C. maximaAphis craccivora, fabae, frangulae, gossypii, spiraecola;
Aulacorthum solani; Brachycaudus helichrysi;
Dysaphis crataegi, [crataegi ssp. kunzei];
Macrosiphum euphorbiae; Myzus ornatus, persicae;
Neomyzus circumflexus; Pseudomegoura magnoliae
C. moschataAphis gossypii, nerii, [ruborum ssp. longisetosus];
Aulacorthum [linderae Shinji (Agarwala et al. 1982)],
solani;
Dysaphis crataegi; Myzus persicae;
Pseudomegoura magnoliae;
C. pepoAcyrthosiphon malvae, [pisum], [vasiljevi];
Aphis craccivora, fabae, frangulae, gossypii, nasturtii;
Aulacorthum solani, spinacaudatum;
Brachycaudus helichrysi; Dysaphis crataegi;
Macrosiphum euphorbiae; Myzus persicae;
Pseudomegoura magnoliae;
[Rhopalosiphoninus latysiphon]; Smynthurodes betae
Cucurbita spp.[Rhopalosiphum nymphaeae]

Key to apterae on Cucurbita (and Cucumis):-

For keys to the common aphids on cultivated Cucurbitaceae see Blackman & Eastop (2000).

1ANT PT/BASE less than 0.5. SIPH absent…..Smynthurodes betae
ANT PT/BASE more than 1. SIPH present…..2
2Cauda helmet-shaped, not longer than its basal width in dorsal view…..3
Cauda tongue- or finger-like, clearly longer than its basal width…..4
3 SIPH pale, truncate conical, 1.1-1.3 × cauda. Spiracular apertures large and rounded …..Brachycaudus helichrysi
SIPH dark, tapering, 1.8-2.3 × cauda. Spiracular apertures reniform …..Dysaphis crataegi
4 Head dark and SIPH mainly pale but contrastingly dark at apices…..5
Head pale or dark, but if dark then SIPH are also wholly dark …..go to key to polyphagous aphids
5SIPH slightly to moderately clavate. Hind tibia dark except for basal 0.1-0.2 of length …..Pseudomegoura magnoliae
SIPH tapering, sometimes with slight swelling of distal half, but no constriction on basal half. Hind tibia dark on about distal half of length…..Aulacorthum spinacaudatum
Cudrania = Maclura
CullenFabaceae
Cullen corylifolium Acyrthosiphon kondoi; Aphis craccivora
C. drupaceum Aphis craccivora
Use key to apterae on Caragana.
CuminumApiaceae
Cuminum cyminum Aphis gossypii; Hyadaphis coriandri; Myzus persicae
C. sativum = C. cyminum
C. setifolium Aphis craccivora

Key to aphids on Cuminum:-

1Head spiculose, with well-developed scabrous ANT tubercles, their inner faces converging apically. SIPH slightly to moderately clavate, about 2 × cauda…..Myzus persicae
Head not spiculose, ANT tubercles undeveloped or weakly developed. SIPH swollen and shorter than cauda, or tapering and longer than cauda…..2
2SIPH pale or dusky-tipped, swollen and a little shorter than cauda …..Hyadaphis coriandri
SIPH dark, tapering and longer than cauda…..3
3Dorsal abdomen without dark sclerotisation. Cauda paler than SIPH …..Aphis gossypii
Dorsal abdomen with an extensive solid black sclerite centred on ABD TERG 4-5. Cauda and SIPH both dark…..Aphis craccivora
Cunninghamia Taxodiaceae
Cunninghamia sp. Mindarus keteleerifoliae
CupheaLythraceae
Cuphea aequipetala Impatientinum americanum
C. appendiculataImpatientinum chiriquense
C. bustamanta Aphis gossypii; Myzus persicae
C. calophyllaImpatientinum paranaense
C. igneaAphis gossypii; Myzus ornatus, persicae
C. infundibulum = C. appendiculata
C. micropetalaAphis gossypii
C. platycentra = C. bustamanta
C. procumbensAphis gossypii; Aulacorthum solani; Myzus ornatus
C. ×purpureaMyzus persicae
Cuphea spp.Acyrthosiphon malvae group;
Impatientinum holmani, oaxacense
Smynthurodes betae

Key to apterae on Cuphea:-

Couplets 2-5 are based on Nieto Nafría et al. (2012).

1SIPH black, with 2-3 rows of transverse striae subapically, or with a few closed polygonal cells, or if with more extensive subapical polygonal reticulation then there is an extensive dark dorsal shield. Head with moderately developed ANT tubercles, with divergent inner faces, and a well developed (but lower) median tubercle…..2
SIPH pale, dark or absent; if dark then there are no subapical transverse striae and the ANT tubercles are weakly developed, or there is more extensive polygonal reticulation but no extensive dark dorsal shield…..go to key to polyphagous aphids
2ANT III-VI mainly or entirely dark…..3
ANT III, IV and V mainly or entirely pale…..4
3ANT I and I as dark as ANT III-VI. Dorsal abdomen with an extensive solid dark shield. HT II at most 0.09 mm, 1.6-1.9 × R IV+V, which bears 15-18 accessory hairs. Dorsal cephalic hairs 37-55 μm…..Impatientinum chiriquense*
ANT I and II much paler than ANT III-VI. Dorsal abdomen without a solid dark shield. HT II at least 0.10 mm long, 1.4-1.6 × R IV+V, which bears 19-33 accessory hairs. Dorsal cephalic hairs 27-37 μm…..Impatientinum paranaense
4SIPH with an extensive, well-defined reticulation; at least 6 rows extending over distal 0.25 of length. R IV+V with less than 10 accessory hairs (based on 1 specimen) …..Impatientinum oaxacense*
SIPH with much less extensive and less well-defined reticulation; at most 5 rows extending over distal 0.13 of length. R IV+V with 10-22 accessory hairs…..5
5Femora with distal parts dark, nearly as dark as tarsi and distal parts of tibiae. BL 3.64-4.75 × longer than SIPH. R IV+V with 17-22 accessory hairs. First tarsal segments mostly with 4 or 5 hairs…..Impatientinum holmani*
Femora pale. BL 4.50-5.50 × longer than SIPH. R IV+V with 10-18 accessory hairs. First tarsal segments mostly with 3, rarely 4, hairs…..Impatientinum americanum
CurculigoHypoxidaceae
Cuculigo capitulata = Molineria capitulata
Cupressocyparis Cupressaceae
Cupressocyparis leylandii Cinara cupressi, fresai; Illinoia morrisoni

Use key to aphids on Cupressus.

Cupressus (incl. Platycladus) Cypresses Cupressaceae

Cupressus has a small but diverse aphid fauna, with no evidence of host specificity at the species level. The only possible confusion is between the Cinara species, which are all in the subgenus Cupressobium.

Cupressus arizonica Cinara cupressi, fresai; Illinoia morrisoni;
(incl. var. glabra) Siphonatrophia cupressi
C. bakeriSiphonatrophia cupressi
C. benthamii see C. lusitanica
C. brunnianasee C. macrocarpa
C. funebrisAphis craccivora; Cinara louisianensis, tujafilina; Illinoia morrisoni
C. glabra see C. arizonica
C. govenianaCinara cupressi
C. guadalupenisCinara fresai; Siphonatrophia cupressi
C. lambertiana = C. macrocarpa
C. lusitanica (incl. var. benthamii) Cinara cupressi, fresai, [juniperi]; Illinoia morrisoni;
[Sanbornia juniperi]; Siphonatrophia cupressi
C. macrocarpa (incl. var. brunniana) Cinara cupressi, fresai, [juniperi]; Illinoia morrisoni;
Siphonatrophia cupressi; Stomaphis cupressi
C. pygmeaCinara fresai; Siphonatrophia cupressi
C. sabiniana (?)Cinara fresai
C. sargentiiSiphonatrophia cupressi
C. sempervirensCinara cupressi, fresai, tujafilina; Illinoia morrisoni;
Siphonatrophia cupressi;
Stomaphis cupressi, cupressi ssp. caucasica
C. torulosaCinara cupressi, fresai; Illinoia morrisoni;
Siphonatrophia cupressi
Cupressus sp.Cinara louisianensis

Key to the aphids on Cupressus:-

1 ANT PT/BASE more than 0.5. Cauda tongue- or finger-shaped, longer than its basal width …..2
ANT PT/BASE less than 0.5. Cauda broadly rounded…..4
2 ANT PT/BASE about 1.0. SIPH pores on very small, shallow cones (fig. 44A) …..Siphonatrophia cupressi
ANT PT/BASE more than 1.3. SIPH tubular, longer than basal width …..3
3 Body spindle-shaped, without dark dorsal markings. SIPH long and markedly swollen on distal half…..Illinoia morrisoni
Body oval, dorsal abdomen with an extensive black patch in aptera and transverse bars in alata. SIPH tapering from base to flange…..Aphis craccivora
4 Rostrum much longer than body…..Stomaphis cupressi
Rostrum much shorter than body…..5
5 Femora pale, and tibiae wholly pale or dark only at apices (sometimes very localised pigmentation at tibio-femoral joints) …..6
Distal parts of femora and bases of tibiae dusky or dark…..7
6 BL often more than 2.4 mm. Aptera with dark sclerites on thorax and ABD TERG 8. Apices of tibiae dark. ANT VI BASE with 8-14 hairs…..Cinara tujafilina
BL less than 2.4 mm. Aptera without dark dorsal sclerites. Apices of tibiae pale or dusky. ANT VI BASE with 5-6 hairs…..Cinara louisianensis
7 ANT VI BASE with 4-6 (-7) hairs restricted to basal half (fig. 44B). R IV with 2-4 accessory hairs. Length of sclerotised part of stylet groove 0.9-1.2 mm. Alata with 1-6 rhinaria restricted to distal half of ANT III…..Cinara cupressi
ANT VI BASE with 7-12 hairs not restricted to basal half (fig. 44C). R IV with 5-7 accessory hairs. Length of sclerotised part of stylet groove 1.3-1.6 mm. Alata with 6-11 rhinaria extending over most of ANT III…..Cinara fresai
CurcumaZingiberaceae
Curcuma domestica = C. longa
C. longaAphis gossypii; Pentalonia kalimpongensis, nigronervosa;
[Rhopalosiphum nymphaeae]

Use key to aphids on Hedychium.

CuscutaConvolvulaceae
Cuscuta approximata Aphis gossypii
C. epithymumAphis cuscutae; Myzus persicae
C. europaeaAphis hederae
C. japonicaAphis gossypii; Sinomegoura citricola
C. lehmannianaBrachyunguis cuscutae
C. lupuliformisAphis fabae
C. monogynaAphis craccivora, hederae; Brachyunguis cuscutae
C. reflexaAphis craccivora, fabae, gossypii, [Aphis sp.; Remaudière
& Etienne 1989);
[Melanaphis meghalayensi]; Myzus persicae
C. subinclusaAphis fabae
C. trifolii = C. epithymum
C. umbellataMacrosiphum cuscutae

Key to apterae on Cuscuta:-

1ANT tubercles undeveloped or weakly developed. ABD TERG 1 and 7 with marginal tubercles (MTu)…..2
ANT tubercles well developed. ABD TERG 1 and 7 without MTu…..7
2ANT PT/BASE 0.9-1.0. SIPH very short, hardly longer than their basal widths, and about equal in length to the short, broadly conical cauda, which is about as long as its basal width …..Brachyunguis cuscutae*
ANT PT/BASE 1.3-3.0. SIPH clearly longer than their basal widths, 0.9-2.8 × cauda, which is tongue-shaped, longer than its basal width…..3
3Dorsum with an extensive black shield…..Aphis craccivora
Dorsum without an extensive black shield…..4
4Cauda as dark as SIPH, with 9-18 hairs…..5
Cauda paler than SIPH , with 4-9 hairs…..6
5 R IV+V 0.9-1.3 × HT II. Marginal tubercles infrequent on ABD TERG 2-4…..Aphis fabae
R IV+V 1.35-1.7 × HT II. Marginal tubercles frequently present on ABD TERG 2-4 …..Aphis hederae
6SIPH 0.9-2.5 × cauda, which bears 4-8 hairs (usually 5-6). No postsiphuncular sclerite. Longest hair on ANT III 0.4-0.8 × BD III…..Aphis gossypii
SIPH 2.5-2.9 × cauda, which bears 6-9 hairs (usually 7-8). SIPH with a dark sclerotic area just posterior to the base. Longest hair on ANT III 0.8-1.0 × BD III …..Aphis cuscutae
7 Head spiculose, with inner faces of ANT tubercles apically convergent. SIPH mainly pale and slightly clavate…..Myzus persicae
Head smooth with inner faces of ANT tubercles divergent. SIPH dark at least on distal half and cylindrical/tapering…..8
8SIPH wholly dark, contrasting with and distinctly longer than the pale cauda. SIPH with polygonal reticulation on distal 0.11-0.16 of length …..Macrosiphum cuscutae
SIPH pale on about basal third, not longer than cauda, which is black. SIPH without distal polygonal reticulation…..Sinomegoura citricola
Cussonia Araliaceae
Cussonia natalensis Macrosiphum euphorbiae
C. paniculataAphis odinae, [Aphis sp. (Leonard 1972)]; Myzus persicae
C. spicataAphis fabae, gossypii, odinae
C. umbellifera = Schlefferaumbellifera

(Use key to polyphagous aphids)

CutandiaPoaceae
Cutandia maritima Sipha maydis
CyamopsisFabaceae
Cyamopsis psoraloides =C. tetragonolobus
C. tetragonolobusAcyrthosiphon gossypii; Aphis craccivora, gossypii

Key to apterae on Cyamopsis:-

1Body spindle-shaped. ANT tubercles well developed. SIPH pale, very long and thin, 0.33-0.50 × BL and 2.5-3.5 × cauda…..Acyrthosiphon gossypii
Body oval. ANT tubercle weakly developed. SIPH dark and much shorter …..2
2Dorsum with an extensive black shield. Cauda black like SIPH …..Aphis craccivora
Dorsum pale. Cauda paler than SIPH…..Aphis gossypii
CyanotisCommelinaceae
Cyanotis axillarisAphis fabae, gossypii
C. vaga[Anoecia similiradiciphaga]

Use key to polyphagous aphids.

Cyanussee CentaureaAsteraceae
Cyanus segetum see Centaurea cyanus
CyatheaCyatheaceae
Cyathea aquilinaAphis aurantii, spiraecola
C. araneosaAphis (Toxoptera) aurantii
C. arboreaAphis spiraecola; Macrosiphum ptericolens
C. balanocarpaAphis spiraecola; Macrosiphum cyatheae

Use key to fern-feeding aphids under Polypodium.

CyathulaAmaranthaceae
Cyathula prostrata Aphis gossypii, spiraecola; Myzus persicae
C. tomentosaAphis raji
C. uncinulataMacrosiphum euphorbiae; Myzus ornatus

Key to apterae on Cyathula:-

R IV+V 0.19-0.23 mm long, narrow and pointed, with R V elongated, so that most distal primary hairs are placed 0.04 mm or more from apex. ANT and legs with long, fine-pointed hairs. SIPH dark, 0.6-1.15 X R IV+V, and 1.2-2.0(-2.4) x longer than the short dark triangular cauda…..Aphis raji
Without this combinaton of characters…..go to key to polyphagous aphids
CycasCycadaceae
Cycas circinalisCerataphis brasiliensis
Cycas sp.Aphis gossypii

Couplet for separating these two species:-

Body dorsoventrally flattened, almost circular, wholly sclerotic with a distinct crenulate margin. Head with a pair of anteriorly directed horns. SIPH as pores ….. Cerataphis brasiliensis
Body oval, of normal aphid form. Head without horns. SIPH tubular …..Aphis gossypii
CyclamenPrimulaceae
Cyclamen cilicium Rhopalosiphoninus staphyleae
C. europaeumAphis gossypii; Myzus persicae; Neomyzus circumflexus
C. indicumAphis gossypii; Aulacorthum solani; Myzus persicae;
Neomyzus circumflexus
C. persicumAphis gossypii; Aulacorthum solani; Myzus persicae;
Neomyzus circumflexus
Cyclamen spp.Aphis fabae; Macrosiphum euphorbiae;
Myzus ornatus, [langei]; Rhopalosiphoninus latysiphon

Use key to polyphagous aphids.

Cyclobalanopsis see QuercusFagaceae
CyclolomaChenopodiaceae
Cycloloma atriplicifolium Macrosiphum euphorbiae
Cyclophorus see PyrrosiaPolypodiaceae
CyclosorusThelypteridaceae
Cyclosorus acuminatus Macromyzella polypodicola
C. aridusMacromyzella polypodicola
C. parasiticaMacromyzella polypodicola
Cyclospermum Apiaceae
Cyclospermum leptophyllum Dysaphis apiifolia
Cydonia Quinces Rosaceae
Cydonia japonica = Chaenomeles japonica
C. malus (= oblonga?) Aulacorthum solani
C. oblongaAnuraphis farfarae;
Aphis aurantii, craccivora, fabae, gossypii, pomi,
spiraecola;
[Aploneura ampelina]; Aulacorthum solani;
Brachycaudus persicae; Dysaphis plantaginea, pyri;
Eriosoma flavum, lanigerum, lanuginosum, pyricola;
Macrosiphum euphorbiae; Myzus ornatus, persicae;
Nearctaphis bakeri, crataegifoliae;
Ovatus crataegarius, insitus; Phorodon humuli;
Pterochloroides persicae;
Rhopalosiphum oxyacanthae, [padi]; [Sappaphis piri];
Sitobion avenae; Watabura nishiyae
C. sinensis = Chaenomeles sinensis
C. vulgaris = Cydonia oblonga
Cydonia sp.[Prociphilus corrugatans]

Key to apterae on Cydonia:-

[See Blackman & Eastop (2000) for a key to the more common aphids on Quince. Distinguishing characters of apterae of Watabura nishiyae are presumed, as this species is only known from alate sexuparae.]

1ANT PT/BASE less than 1. SIPH absent, pore-like or as pigmented hairy cones …..2
ANT PT/BASE more than 1. SIPH tubular…..7
2SIPH in form of large pores on large pigmented cones bearing numerous hairs. Abdomen with a double row of large dark spinal tubercles…..Pterochloroides persicae
SIPH pore-like surrounded by a single ring of hairs, or absent. No dark spinal tubercles …..3
3SIPH absent. R IV+ V shorter than HT II …..Watabura nishiyae (a Prociphilus sp.?)*
SIPH present as pores with partially sclerotized rims. R IV+V longer than HT II …..4
4Distinct dorsal abdominal wax pore plates present, consisting of groups of cells each enclosing a very small, narrow or subdivided central area (on roots, trunk or branches) …..Eriosoma lanigerum
Dorsal abdominal wax pore plates absent or present, if present then each consists of a ring of cells around a large central undivided area (on roots only)…..5
5BL 2.0-2.7 mm. R IV+V 0.22-0.25 mm. (Cauda with 2-4 hairs) …..Eriosoma lanuginosum
BL 1.0-1.9 mm. R IV+V 0.10-0.18 mm…..6
6BL 1.0-1.3 mm. R IV+V 0.10-0.12 mm. Cauda with 2-4 hairs …..Eriosoma flavum
BL 1.3-1.9 mm. R IV+V 0.12-0.18 mm. Cauda with 5 or more hairs …..Eriosoma pyricola
7ANT tubercles undeveloped or weakly developed…..8
ANT tubercles well-developed…..20
8SIPH short, with closely spaced rows of spinules or nodules…..9
SIPH longer, with sparser, normal imbrication, or if short then smooth…..11
9Cauda broadly rounded, much shorter than its basal width. Most segments with paired spinal tubercles (STu). (Leaf galls containing fundatrix and emigrant alatae only) ……Anuraphis farfarae
Cauda 0.6-1.3 times as long as its basal width. STu absent. (Not forming leaf galls) …..10
10 SIPH 0.8-1.1 × cauda, which is 1.0-1.3 × its basal width and bears 6-7 hairs. R IV+V 0.10-0.13 mm long, and usually with 2 accessory hairs. (Al. with a solid black dorsal  …..Nearctaphis bakeri
SIPH 1.1-1.6 × cauda, which is 0.6-1.0 × its basal width, and bears 8-12 hairs. R IV+V 0.14-0.18 mm long, and usually with 4 accessory hairs. (Al. without a solid black dorsal …..Nearctaphis crataegifoliae
11Cauda short and broad, helmet-shaped……12
Cauda tongue-shaped, clearly longer than its basal width in dorsal view …..15
12SIPH pale, smooth, truncate, less than 1.4 × cauda …..Brachycaudus helichrysi
SIPH dark, imbricated, tapering, more than 1.5 × cauda…..13
13Dorsum covered with an extensive black shield, extending to marginal sclerites. Spinal tubercles (STu) absent from head, rarely present on ABD TERG 8 only …..Brachycaudus persicae
Dorsum without an extensive black shield. STu usually present on head and ABD TERG 7-8…..14
14SIPH 0.14-0.20 × BL. ANT PT/BASE 3.6-5.7…..Dysaphis plantaginea
SIPH 0.07-0.12 × BL. ANT PT/BASE 2.2-3.2…..Dysaphis pyri
15SIPH cylindrical over much of length, slightly swollen distally, with a constriction just proximal to flange…..Rhopalosiphum oxyacanthae
SIPH tapering from base to flange….16
16Dorsal abdomen with an extensive black patch…..Aphis craccivora
Dorsal abdomen unpigmented or with only scattered dark markings…..17
17ANT PT/BASE more than 3.5. Stridulatory apparatus present, consisting of ventrolateral ridges on abdominal sternites 5 and 6 and a row of peg-like hairs on each hind tibia ……Aphis (Toxoptera) aurantii
ANT PT/BASE less than 3.5. No stridulatory apparatus …..18
18Cauda paler than SIPH, with usually 4-8 hairs (usually 5-6) ……Aphis gossypii
Cauda and SIPH both dark, and cauda with 7-19 hairs…..19
19Marginal tubercles (MTu) present on ABD TERG 2-4. Cauda with 10-19 hairs (rarely less than 13). R IV+V more than 130μm long……Aphis pomi
MTu absent from ABD TERG 2-4. Cauda with 7-15 hairs (rarely more than 12). R IV+V less than 120μm long……Aphis spiraecola
20 Head smooth, with inner faces of ANT tubercles divergent. SIPH with a subapical zone of polygonal reticulation…..21
Head spiculose, with inner faces of ANT tubercles parallel or convergent. SIPH without any polygonal reticulation…..23
21SIPH 1.1-1.4 × cauda with reticulation on distal 0.19-0.35 of length. Hairs on ANT III 0.3-0.5 × BD III…..Sitobion avenae
SIPH 1.7-2.4 × cauda with reticulation on distal 0.1-0.2 of length, hairs on ANT III 0.6-1.1 × BD III…..22
22Head and SIPH dark. ANT III with 10-35 rhinaria…..Macrosiphum rosae
Head and SIPH pale. ANT III with 1-10 rhinaria …..Macrosiphum euphorbiae
23Inner faces of ANT tubercles approximately parallel in dorsal view. ANT III usually with 1-3 small rhinaria near base…..Aulacorthum solani
Inner faces of ANT tubercles convergent, or bearing scabrous rounded or finger-like processes. ANT III without any rhinaria…..24
24Inner faces of ANT tubercles bearing long, finger-like processes …..Phorodon humuli
Inner faces of ANT tubercles without finger-like processes…..25
25Dorsal abdomen with an intersegmental pattern of dark ornamentation. ANT PT/BASE 1.7-2.8…..Myzus ornatus
Dorsal abdomen without any dark ornamentation. ANT PT/BASE 2.8-8 ……26
26SIPH slightly clavate. ANT VI pale, with PT/BASE 2.8-4.5 …..Myzus persicae
SIPH tapering from base to flange. ANT VI dark, with PT/BASE 5-8…..27
27Al. (spring emigrant) with 60-83 rhinaria on ANT III, 36-42 on IV and 13-22 on V …..Ovatus insitus
Al. (spring emigrant) with 22-49 rhinaria on ANT III, 5-20 on IV and 0-10 on V …..Ovatus crataegarius
Cylactis see RubusRosaceae
Cylactis pubescens see Rubus pubescens
Cymbalaria Plantaginaceae
Cymbalaria alpina Myzus cymbalariae
C. muralisBrachycaudus helichrysi; Dysaphis gallica;
Myzus ascalonicus, cymbalariae, [certus], ornatus, persicae
C. pallidaMyzus ascalonicus

Key to apterae on Cymbalaria:-

1 Cauda short, helmet-shaped or pentagonal not more than 1.2 × its basal width in dorsal view…..2
Cauda tongue- or finger-like, more than 1.3 × its basal width in dorsal view …..go to key to polyphagous aphids
2 SIPH smooth, pale 0.8-2.0 × cauda. Head smooth with ANT tubercles and median frontal tubercle undeveloped. Spiracular apertures large and rounded …..Brachycaudus helichrysi
SIPH imbricated, dark at least towards apices, 2.4-3.3 × cauda. Head with evident ANT tubercles and a scabrous median frontal tubercle. Spiracular apertures small and reniform …..Dysaphis gallica
CymbariaOrobanchaceae
Cymbaria borysthenica Macrosiphoniella cymbariae
CymbidiumOrchidaceae
C. aloifoliumCerataphis orchidearum
C. densiflorum = C. elegans
C. eburneumNeomyzus circumflexus; Sitobion indicum, pseudoluteum
C. elegansSitobion indicum, pseudoluteum
C. ensifolium var. munroniamum Sitobion indicum
C. grandiflorum = C. hookerianum
C. hookerianumCerataphis orchidearum; Neomyzus circumflexus
C. iridifolium = C. madidum
C. longifolium = C. elegans
C. lowianumAphis fabae; Cerataphis orchidearum; Myzus persicae;
Sitobion indicum
C. luteum =Chloraea gravilu
C. madidum Sitobion indicum
C. montanum = Dilomilis montana
C. munronianum = C. ensifolium var. munronianum
C. suaveCerataphis orchidearum
C. tracyanumSitobion indicum
Cymbidium sp.Aphis gossypii, nasturtii; Aulacorthum solani;
Macrosiphum euphorbiae; Myzus ornatus

Key to apterae on Cymbidium and most other orchid genera:-

(For a key to the common aphids on cultivated orchids see Blackman & Eastop 2000)

1Body dorso-ventrally flattened, almost circular, wholly sclerotic, with a continuous marginal fringe of wax glands, and a pair of horns projecting forward anteriorly (Fig.25a). SIPH as large round pores raised on shallow cones. Cauda knobbed, anal plate bilobed …..Cerataphis orchidearum
Body oval, not wholly sclerotic, without marginal wax glands or horns. SIPH tubular, Cauda helmet- or tongue-shaped, anal plate entire…..2
2SIPH wholly dark, with a subapical zone of polygonal reticulation (sometimes only a few closed polygonal cells)…..3
SIPH pale or dark, but if wholly dark then without any trace of subapical polygonal reticulation…..8
3Dorsal hairs long and conspicuous, those on anterior ABD TERG 1.0-1.8 × ANT BD III. Longest hair on ANT III 0.5-1.0 × BD III. SIPH 1.1-1.33 × cauda, and only reticulated on less than 0.14 of length. ABD TERG 1-5 usually with dark sclerotisation extending to margins…..4
Anterior dorsal abdominal and ANT hairs very short and inconspicuous, less than 0.4 × BD III. SIPH 1.4-2.3 × cauda, and reticulated on distal 0.2 or more of length. ABD TERG 1-5 either unsclerotised or with a central dark patch not extending to margins …..5
4First tarsal segments with 4 hairs. Longest hairs on ANT III 0.8-1.0 × BD III …..Sitobion pseudoluteum*
First tarsal segments usually with 3 hairs. Longest hairs on ANT III 0.5-0.7 × BD III …..Sitobion orchidacearum
5Abdominal tergum membranous. SIPH 1.9-2.3 × cauda…..6
Abdominal tergum with a dark patch. SIPH 1.4-2.0 × cauda…..7
6ANT shorter than BL, and pale except for apices of segments III-V and PT. ANT PT/BASE 3.9-6.2. Cauda 0.17-0.23 mm long, 1.2-1.6 × its basal width …..Sitobion anselliae
ANT much longer than BL, and dark except for I-II and base of III. ANT PT/BASE 6.2-8.0. Cauda 0.26-0.35 mm long, 1.6-2.0 × its basal width…..Sitobion eulophiae
7Cauda with 6-8 hairs. Dorsal abdominal patch broadly oval with only small marginal indentations (Fig.25b). ANT III slightly constricted at base in comparison to rhinariated part …..Sitobion luteum
Cauda with 9-13 hairs. Dorsal abdominal patch very irregular in outline with large intersegmental indentations (Fig.25c). ANT III as thick at base as at rhinariated part …..Sitobion indicum
8Dorsum with a distinctive pattern of black markings, comprising paired pleuro-spinal and marginal sclerites on prothorax, metanotum and ABD TERG 1-7, and a medial sclerite on ABD TERG 8 (Fig.25d). SIPH asymmetrically swollen on distal half …..Neomyzus dendrobii
Dorsum without such a pattern; if with any dark markings then SIPH are not swollen on distal half…..9
9Dorsal abdomen with a solid dark oval sclerite centred on ABD TERG 2-4, otherwise pale except for thin cross band on ABD TERG 8. SIPH black, cylindrical, slightly narrower at midlength. Head densely spiculose, with well-developed ANT tubercles.. ANT PT/BASE 2.9-3.3 …..?Micromyzus sp. on Dendrobium sulphureum, New Guinea
Without that combination of characters; if dorsal abdomen has a central sclerite then it is broken in midline and ANT PT/BASE 3.5-5.3. SIPH and head various …..10
10 Cauda helmet-shaped, not longer than its basal width, with 4-5 hairs. R IV+V 1.5-1.8 × HT II, similar in length to SIPH…..Dysaphis neostroyani
Cauda tongue-shaped, longer than its basal width, with 4-24 hairs. R IV+V 0.9-1.4 × HT II, shorter than SIPH…..11
11SIPH thick and cylindrical, c.0.8 × cauda. ANT PT/BASE c.1.9. ABD TERG 1 and 7 with marginal tubercles (MTu)…..Aphis orchidis*
Without that combination; either or both SIPH and ANT PT relatively longer. ABD TERG 1 and 7 with or without MTu…..12
12SIPH and cauda both entirely black, the latter without any midway constriction and bearing 11-24 hairs. Thorax and ABD TERG 7 and 8 with dark cross-bands, and usually scattered small dark markings also on ABD TERG 1-6. ANT tubercles weakly developed and ABD TERG 1 and 7 with MTu. No stridulatory apparatus…..13
Without that combination of characters …..go to key to polyphagous aphids
13Hairs on ANT III very fine, the longest 2.1-2.8 × BD III. R IV+V 1.05-1.25 × HT II. MTu often present on ABD TERG 2-6 as well as 1 and 7…..Aphis epipactis
Longest hairs on ANT III 0.6-2.2 × BD III. R IV+V 0.9-1.1 × HT II. MTu rarely present on ABD TERG 2-6…..Aphis fabae group (incl. A. solanella)
CymbopogonPoaceae
C. citratusSipha flava
C. martiniSitobion miscanthi; Tetraneura akinire
C. nardusSitobion miscanthi, [Sitobion sp. (Millar 1994)];
C. tortilis[Pemphigus andropogiae Shinji 1924];
[Watabura nishiyae]
C. validus = C. nardus
Cymbopogon sp.Rhopalosiphum padi; Schizaphis hierochlophaga

Use key to apterae of grass-feeding aphids under Digitaria.

Cymboseris see CrepisAsteraceae
CynanchumApocynaceae
C. acutum (incl. ssp. sibiricum) Aphis craccivora, fabae, gossypii, nerii;
Brachyunguis bicolor, cynanchi
C. atratumAphis asclepiadis, nerii; Myzus persicae
C. dalhousiaeAphis nerii
C. ellipticumAphis nerii
C. racemosum (var. rensonii) Aphis nerii, spiraecola
C. salinarum = Funastrum angustifolium
C. savannarumAphis nerii
C. sibiricum = C. acutum ssp. sibiricum

Key to apterae on Cynanchum:-

1. ANT PT/BASE more than 2. SIPH longer than cauda …..go to key to apterae on Asclepias
ANT PT/BASE less than 1. SIPH shorter than cauda…..2
2. SIPH 2-3 × longer than their basal widths, 0.75-0.9 × ANT VI (incl. PT), and 0.8-0.95 × cauda, which bears 11-12 hairs…..Brachyunguis cynanchi*
SIPH less than 2 × longer than their basal widths, about 0.6 × ANT VI (incl. PT), and 0.5-0.6 × cauda, which bears about 6 hairs…..Brachyunguis bicolor*
CynaraAsteraceae
Cynara cardunculus Aphis fabae, gossypii, [intybi], spiraecola;
Brachycaudus cardui;
Capitophorus elaeagni, carduinus, horni;
Dysaphis lappae ssp. cynarae; Hyperomyzus lactucae;
Macrosiphum euphorbiae; Myzus persicae;
Protrama flavescens, radicis; Trama troglodytes;
Uroleucon compositae, jaceae, sonchi
C. cynosbatella (?) Aphis fabae ssp.?cirsiiacanthoides (as neoreticulata
Theobald 1927)
C. humilisAphis fabae
C. scolymusAphis craccivora, fabae, gossypii, solanella;
Aulacorthum solani; Brachycaudus cardui, helichrysi;
Capitophorus [carduinus], elaeagni, horni, [similis];
Dysaphis lappae ssp. cynarae; Macrosiphum euphorbiae;
Myzus ascalonicus, persicae;
[Pleotrichophorus chrysanthemi];
Protaphis middletonii, terricola;
Protrama radicis; Trama troglodytes;
Uroleucon cichorii, compositae, gobonis, jaceae

Key to apterae on Cynara (and Silybum):-

1 ANT PT/BASE less than 0.7. HT II elongate, at least 0.5 × hind tibia …..2
ANT PT/BASE more than 0.75. HT II of normal length…..4
2SIPH absent. Apterae without dark dorsal markings. ANT VI shorter than ANT V, with ANT PT/BASE 0.14-0.25…..Trama troglodytes
SIPH present as large pores on low pigmented cones. Most apterae alatiform, with dark dorsal markings. ANT VI longer than ANTV, with ANT PT/BASE 0.4-0.6 …..3
3HT II 0.72-0.87 × length of hind tibia. Hind tibia 5.0-6.4 × ANT IV. R IV with 8-12 accessory (dorsal) hairs….. Protrama radicis
HT II 0.59-0.70 × length of hind tibia. Hind tibia 6.5-9.2 × ANT IV. R IV with 6-8 accessory (dorsal) hairs…..Protrama flavescens
4 Cauda short, helmet-shaped or bluntly triangular, shorter than or not clearly longer than its basal width in dorsal view…..5
Cauda elongate triangular, tongue-or finger-shaped, clearly longer than its basal width in dorsal view…..9
5 ANT PT/BASE 0.75-2.1. ABD TERG 1 and 7 with well-developed marginal tubercles (MTu). Cauda bluntly triangular with 10-20 hairs…..6
ANT PT/BASE 2.3-5.1. Cauda helmet-shaped, with 5-8 hairs. If ABD TERG 1 and 7 have MTu then these are also present on ABD TERG 2-5 …..7
6ANT PT/BASE 0.75-1.15, and PT 0.5-0.8 × R IV+V…..Protaphis terricola
ANT PT/BASE 1.4-2.1, and PT 0.8-1.2 × R IV+V…..Protaphis middletonii
7Dorsal abdomen with an extensive solid black patch. SIPH 0.10-0.15 × BL. Mesosternum with a pair of dark mammariform processes…..Brachycaudus cardui
Dorsal abdomen without a solid black patch, at most with scattered dark markings. SIPH 0.05-0.10 × BL. Mesosternum without mammariform processes…..8
8BL 0.9-2.0 mm. SIPH smooth, short and broad-based, 1.5-2.0 × their diameter at midlength. Spinal and marginal tubercles (STu and MTu) rare or absent ……Brachycaudus helichrysi
BL 2.1-3.0 mm. SIPH imbricated and about 3 × their diameter at midlength. Numerous well-developed STu and MTu present…..Dysaphis lappae ssp. cynarae
9Hairs on front of head and dorsal body mostly capitate, often quite long and arising from tuberculate bases…..10
Hairs on front of head and dorsal body not capitate…..12
10Dorsal abdomen with most spinal hairs duplicated, not arranged in two clear longitudinal rows …..Capitophorus horni
Dorsal abdomen with one pair of spinal hairs per segment, forming a single longitudinal row on each side of mid-line…..11
11 Cauda 1.4-2.3 × R IV+V, and bearing 7-13 hairs. ANT PT 4.5-6.3 × R IV+V, and 6.0-9.2 × ANT BASE VI. SIPH with dark apices…..Capitophorus elaeagni
Cauda 1.1-1.5 × R IV+V, and bearing 5-8 hairs. ANT PT 3.1-4.4 × R IV+V, and 4.6-6.3 × ANT VI BASE. SIPH without dark apices…..Capitophorus carduinus
12 SIPH pale and markedly clavate, with maximum diameter of swollen part 1.4-2.0 × minimum diameter on basal half. Head smooth…..Hyperomyzus lactucae
SIPH pale or dark; tapering, cylindrical, or if clavate then head is spiculose …..13
13 SIPH pale or dark, but if dark then without any subapical polygonal reticulation …..go to polyphagous aphids key
SIPH mainly or wholly dark, and with a subapical zone of polygonal reticulation …..14
14 Cauda dark like SIPH……15
Cauda pale, much paler than SIPH…..17
15 ANT III with 48-86 rhinaria extending over 0.85-0.92 of length of segment. Cauda with 10-22 hairs. ABD TERG 2-4 usually without marginal tubercles (MTu)…..Uroleucon compositae (or gobonis)
ANT III with 20-54 rhinaria on basal 0.35-0.68 (-0.88) of length. Cauda with 22-30 hairs. ABD TERG 2-4 often with MTu…..16
16R IV+V 0.23-0.26 mm long. ABD TERG 2-4 with MTu present that are often larger than adjacent hair-bases. Tibiae usually slightly paler on middle part. Hind tibia without a row of peg-like hairs on inner side….. Uroleucon aeneum
R IV+V 0.17-0.225 mm long. ABD TERG 2-4 with MTu if present not larger than adjacent hair-bases. Tibiae usually entirely black. Hind tibia with a row of very short and thick peg-like hairs on the inner side…..Uroleucon jaceae
17 Dorsal hairs on ABD TERG 1-5 not placed on dark scleroites. RVI+V 0.73-0.88 × HT II …..Uroleucon sonchi
Dorsal hairs on ABD TERG 1-5 all or mostly placed on dark scleroites. R IV+V 1.17-1.33 × HT II…..Uroleucon cichorii
CynodonPoaceae
Cynodon dactylon Anoecia corni, vagans; Aphis gossypii, spiraecola;
Aploneura lentisci; Asiphonella cynodonti, dactylonii;
Baizongia pistaciae; Ceratovacuna panici;
Chaetogeoica polychaeta; Diuraphis noxia;
Forda formicaria, hirsuta, marginata;
Geoica lucifuga, utricularia; Hysteroneura setariae;
[Iziphya maculata]; Paracletus bykovi, cimiciformis;
Rhopalosiphum maidis, padi, rufiabdominale;
Schizaphis graminum, rotundiventris; Sipha flava, maydis;
Sitobion africanum, avenae, lambersi, leelamaniae, miscanthi;
Smynthurodes betae;
Tetraneura africana, caerulescens, akinire, nigriabdominalis, radicicola, ulmi
C. plectostachyusBrachysiphoniella montana; [Pterasthenia shiraensis];
Sitobion graminis
Cynodon sp.Ceratovacuna cynodonti

Use key to apterae of grass-feeding aphids under Digitaria.

CynoglossumBoraginaceae
Cynoglossum amabile Brachycaudus helichrysi
C. creticumBrachycaudus bicolor, helichrysi
C. denticulatum = C. wallichii
C. furcatum = C. zeylanicum
C. glochidiatum = C. wallichii ssp. glochidiatum
C. grandeBrachycaudus bicolor; Myzus persicae
C. hungaricum = C. montanum
C. lanceolatumAphis gossypii; Brachycaudus helichrysi;
Myzus ornatus
C. montanumBrachycaudus cardui
C. nebrodenseAphis craccivora; Brachycaudus helichrysi
C. officinaleAcyrthosiphon malvae; Aphis symphyti;
Brachycaudus bicolor, cardui, helichrysi, lateralis;
[Diuraphis frequens]; Myzus persicae (incl. ssp.)
C. pictum = C. creticum
C. wallichii (glochidiatum)[Aleurodaphis blumeae]; Allocotaphis multisetosa*; Brachycaudus helichrysi;
[Longisiphoniella subterranea]; Myzus ornatus;
[Protrama longitarsus ssp. sclerodensis]
C. zeylanicumAphis gossypii; Brachycaudus helichrysi
Cynoglossum spp. Aphis [cynoglossi Lichtenstein 1884], fabae, nasturtii,
Aphis sp. ?tirucallis (BMNH colln, Iran);
[Cerataphis lataniae]; [Eutrichosiphum flavum];
Macrosiphum euphorbiae; Neomyzus circumflexus;
[Rhopalosiphum padi]; [Uroleucon pseudotanaceti]

Key to apterae on Cynoglossum:-

1Cauda helmet-shaped, not longer than its basal width in dorsal view…..2
Cauda tongue or finger-shaped, clearly longer than its basal width…..6
2SIPH 0.23-0.29 × BL and 5.9-8.1 × cauda. ANT 0.7-0.9 × BL, with PT/BASE 4.6-8.1. Marginal and spinal tubercles absent…..Allocotaphis multisetosa*
SIPH 0.05-0.16 × BL and 1.1-3.4 × cauda. ANT 0.4-0.8 × BL, with PT/BASE 2.4-5.1. Marginal and spinal tubercles present or absent…..3
3 Dorsum without any dark markings. SIPH 0.05-0.10 × BL …..Brachycaudus helichrysi
Dorsum with a dark shield or extensive dark markings. SIPH 0.09-0.15 × BL …..4
4Broad, flat, pale marginal tubercles (MTu) present on ABD TERG 1-7, larger than the spiracles and occupying almost the whole of the sclerites on which they are placed. ABD TERG 7 often, and 6-8 sometimes, with spinal tubercles (STu)…..Brachycaudus bicolor
MTu irregularly present on ABD TERG 2-4, sometimes also on 1 and/or 5, but never on 6 and 7, and generally smaller than the spiracles. No STu…..5
5 Longest hairs on hind femur 10-25 mm…..Brachycaudus lateralis
Longest hairs on hind femur more than 25 mm long…..Brachycaudus cardui
6 ANT tubercles weakly developed. ABD TERG 1 and 7 with marginal tubercles (MTu) …..7
ANT tubercles well developed. ABD TERG 1 and 7 without MTu …..go to key to polyphagous aphids, starting at couplet 4
7Dorsal abdomen with a (sometimes fragmented) black shield. R IV+V 0.9-1.01 × HT II. Cauda with 4-8 hairs …..8
Dorsal abdomen either with dark cross-bands or pale. R IV+V 0.88-1.57 × HT II. Cauda with 4-25 hairs…..9
8ANT PT/BASE 1.4-1.6. SIPH 0.6-1.0 × cauda …..Aphis sp. (?tirucallis – Iran, BMNH collection)
ANT PT/BASE 1.7-2.8. SIPH 1.1–2.1 × cauda…..Aphis craccivora
9Cauda black with 11-25 hairs. Dorsal abdomen usually with transverse dark bands on ABD TERG 7 and 8, and often with dark markings on more anterior tergites …..Aphis fabae
Cauda paler than SIPH, with 4-11 hairs. Dorsal abdomen without dark markings, or with only narrow bands on ABD TERG (7) – 8…..10
10SIPH usually rather pale, darker at apices. R IV+V 1.0-1.2 × HT II …..Aphis nasturtii
SIPH uniformly dark. R IV+V 1.1-1.57 × HT II…..11
11Total length of rostrum (measured from base of protractor apodeme) 0.43-0.60 mm, 0.27-0.36 × BL. (Al. with 1-4 rhinaria n ANT III)…..Aphis symphyti
Total length of rostrum 0.34-0.49 mm, 0.22-0.28 × BL. (Al. usually with 0, rarely with 1-2, rhinaria on ANT III)…..Aphis gossypii
CynoglottisBoraginaceae
Cynoglottis barrelieri Brachycaudus helichrysi
CynometraFabaceae
Cynometra cauliflora Aphis aurantii, gossypii

(Use key to polyphagous aphids)

CynosurusPoaceae
Cynosurus cristatus Anoecia corni; Atheroides serrulatus; Forda formicaria;
Metopolophium festucae ssp. cerealium;
Pemphigus sp. (?groenlandicus – Zwölfer 1958);
Rhopalosiphum padi; Sitobion avenae, fragariae
C. echinatusMetopolophium dirhodum, fasciatum;
Rhopalosiphum padi; Sitobion avenae, fragariae
C. elegansMetopolophium dirhodum; Sitobion fragariae

Use key to apterae of grass-feeding aphids under Digitaria.

Cynura =GynuraAsteraceae
CypellaIridaceae
Cypella herbertiiHysteroneura setariae
Cyperorchis =CymbidiumOrchidaceae
Cyperus (including Mariscus) Cyperaceae
Cyperus aggregatusCarolinaia caricis, cyperi
C. ajax[Sitobion sp.]
C. alopecuroidesSchizaphis rotundiventris
C. alternifoliusRhopalosiphum padi
C. amabilisSchizaphis minuta
C. australis = C. glomeratus
C. bacans (?)Carolinaia scirpi
C. badiusSchizaphis pyri (as fritzmuelleri), rotundiventris;
Sipha glyceriae
C. brevifolius = Kyllinga brevifolia
C. compressusHysteroneura setariae
C. congestusHysteroneura setariae
C. cylindristachyus Hysteroneura setariae; Schizaphis rotundiventris
C. cyperoidesCarolinaia scirpi; Hysteroneura setariae;
Schizaphis rotundiventris
C. difformis[Ovatus malisuctus]; Rhopalosiphum nymphaeae;
Schizaphis (Paraschizaphis) sp. nr acori (Japan, BMNH collection)
C. distachyosAphis fabae, [polyanthis Passerini 1843: Macchiati 1884]
C. elatusSchizaphis rotundiventris
C. eragrostisCeruraphis eriophori; Sitobion avenae
C. esculentusAphis gossypii; Carolinaia cyperi; Hysteroneura setariae;
Rhopalosiphum maidis, rufiabdominale;
Saltusaphis scirpus;
Schizaphis minuta, rotundiventris; Sipha flava;
Sitobion hillerislambersi, [Sitobion sp. (Millar 1994)];
Smynthurodes betae
C. exaltatusSchizaphis hypersiphonata, rotundiventris
C. fastigiatusRhopalosiphum maidis
C. flabelliformisCarolinaia scirpi, javanica; Sitobion miscanthi
C. flavus = C. aggregatus
C. flexuosusCarolinaia caricis, cyperi
C. fuscusNevskya fungifera; Saltusaphis scirpus
C. glomeratus Rhopalosiphum padi
C. haspanCarolinaia javanica
C. hermaphroditusCarolinaia corozonensis, cyperi
C. imbricatusAphis gossypii
C. inconpletus = C. hermaphroditus
C. iriaHysteroneura setariae; Saltusaphis scirpus
C. laevigatusAphis fabae
C. longusRhopalosiphum padi; Saltusaphis scirpus;
Schizaphis graminum, [scirpi], pyri, rotundiventris;
Sipha glyceriae; Sitobion avenae; Tetraneura africana
C. malaccensis (incl. var. brevifolius)Vesiculaphis caricis
C. microiriaRhopalosiphum rufiabdominale; Vesiculaphis caricis
C. monophyllus = C. malaccensis var. brevifolius
C. niveusSchizaphis graminum
C. odoratusCarolinaia cyperi
C. pagrus (?)Hysteroneura setariae; Schizaphis rotundiventris
C. papyrusSchizaphis rotundiventris
C. pilosusSchizaphis rotundiventris
C. pseudoleptocladus [Sitobion sp. (Millar 1994)]
C. pustulatusAphis gossypii
C. reduncusAphis gossypii
C. rigidifoliusRhopalosiphum maidis; Saltusaphis scirpus;
Schizaphis rotundiventris
C. rotundifoliusCeruraphis eriophori
C. rotundusAphis fabae, gossypii, [nerii]; Carolinaia cyperi;
Forda formicaria; Geoica lucifuga; Hysteroneura setariae;
Nevskya fungifera; [Paracletus bykovi ssp. uzbekistanicus];
Rhopalosiphum maidis, nymphaeae, padi, rufiabdominale;
Schizaphis graminum, minuta, piricola, pyri, rotundiventris;
Sitobion miscanthi; Tetraneura akinire, radicicola;
[Therioaphis trifolii ssp. maculata, ononidis];
[Thripsaphis ballii]; Vesiculaphis caricis
C. serotinusSchizaphis minuta, [Schizaphis sp.], [Schizaphis
(Paraschizaphis) sp.];
Sitobion avenae, miscanthi group; Vesiculaphis caricis
C. sumatrensis = Killinga sumatrensis (?)
C. umbellatus = C. cyperoides
C. usitatusSaltusaphis scirpus
C. vegetus = C. eragrostis
C. virensGeoica utricularia
Cyperus spp.Acutosiphon obliquoris;
Allaphis cyperi, ossiannilsoni, [producta];
[Colopha compressa]; Forda hirsuta;
Melanaphis donacis;
Metopolophium dirhodum, festucae; [Pseudaphis sijui];
Sitobion africanum, graminis; [Subsaltusaphis sinensis]

Key to apterae on Cyperus:-

1 SIPH tubular; tapering, cylindrical or swollen, clearly longer than their basal widths …..2
SIPH in form of short truncate cones not clearly longer than their basal widths, or present merely as pores, or completely absent…..31
2 SIPH tapering to a point, with aperture placed laterally. ANT 5-segmented, with PT/BASE less than 1…..Acutosiphon obliquoris
SIPH cylindrical or swollen, with terminal aperture. ANT 5- or 6-segmented, with PT/BASE more or less than 1…..3
3 Head flattened, with frontal area produced into a ledge extending over ANT bases. SIPH stout, very scabrous, swollen over most of length and very strongly constricted before apex; width in middle 60-95 mm, 0.22-0.26 × length and 3.4-5.4 × width of subapical constriction …..Vesiculaphis caricis
Head not flattened or extended forward over ANT bases. SIPH scabrous, imbricated or smooth, but if scabrous, swollen and subapically constricted then the swollen part is less than 2.5 × width of constriction…..4
4Head with inner sides of ANT tubercles scabrous, or developed as rounded, scabrous or spiculose processes…..5
Head with ANT tubercles absent, or weakly developed, or smooth and divergent …..6
5ANT 2.7-3.7 × head width across (and including) eyes. ANT III 2.3-2.6 × ANT V, and 2.9-4.0 × BASE VI. R IV+V 1.2-1.3 × HT II and bearing 4-5 accessory hairs…..Carolinaiascirpi
ANT 2.1-2.5 × head width across eyes. ANT III 1.5-1.7 × ANT V, and 1.9-2.2 × BASE VI. R IV+V 0.9-1.0 × HT II, and bearing 2 accessory hairs …..Carolinaia javanica
6ANT 5-segmented, bearing long hairs up to 4-5 × BD III. ANT PT/BASE 4.5-5.9, with PT usually curved. (When rarely 6-segmented then ANT PT 2.0-2.5 × ANT III) …..Rhopalosiphum rufiabdominale
ANT 5- or 6-segmented, but if 5-segmented then hairs are much shorter and/or ANT PT/BASE is less than 3.6. ANT PT 0.9-2.0 × ANT III…..7
7SIPH scabrous dorsally and with heavy, denticulate imbrication ventrally; swollen or thickened on distal half and constricted subapically, so that maximum diameter of swollen part is more than 1.7 × diameter of subapical constriction. Dorsal cuticle sclerotic and strongly wrinkled or pitted…..8
SIPH smooth or normally imbricated, or heavily imbricated but with maximum diameter of distal half less than 1.6 × diameter of subapical constriction. Dorsal cuticle sclerotic or membranous…..10
8ANT 0.26-0.31 × BL, often 5-segmented, with ANT PT/BASE 1.0-1.5…..Carolinaia caricis
ANT usually 6-segmented, 0.4-0.55 × BL, with ANT PT/BASE 2.0-2.6 …..9
9Total length of rostrum 0.14-0.17 × BL. SIPH thick, 3.9-4.5 × maximum diameter of swollen part and 3.7-4.8 × minimum diameter on basal half…..Carolinaia cyperi
Total length of rostrum 0.17-0.22 × BL. SIPH longer and thinner; 5.0-5.8 × maximum diameter of swollen part and 6.5-7.3 × minimum diameter on basal half …..Carolinaia corazonensis
10Cauda 0.8-1.2 × ANT PT and bearing 12-21 hairs. ANT PT/BASE 1-2 …..Melanaphis donacis
Cauda 0.25-0.7 × ANT PT and bearing 4-13 hairs. ANT PT/BASE 1.7-6.3 …..11
11 ANT less than 0.5 × BL…..12
ANT more than 0.5 × BL…..13
12Dorsum with extensive dark sclerotisation. Dorsal hairs long; those on ANT III about 2 × BD III. ANT III with 2-10 rhinaria near base. ANT PT/BASE 2.7-3.6 …..Ceruraphis eriophori
Dorsum pale, not sclerotic. Hairs on ANT III less than 2 × BD III. ANT III without rhinaria. ANT PT/BASE 1.7-2.8…..Rhopalosiphum maidis
13SIPH dark with a subapical zone of polygonal reticulation…..14
SIPH pale or dark, without polygonal reticulation…..18
14Cauda black like SIPH…..Sitobion graminis
Cauda pale or dusky, much paler than SIPH…..15
15SIPH 2.5-3.1 × cauda, which has 5-6 hairs. Dorsal abdomen with a sharply-defined almost oval black central patch…..Sitobion hillerislambersi
SIPH 1.1-1.9 × cauda. Dorsal abdomen with or without dark markings, but without a sharply defined central black patch…..16
16 SIPH 1.1-1.4 × cauda. HT II 1.2 -1.6 × R IV+V…..Sitobion avenae
SIPH 1.4-1.9 × cauda. HT II 1.0-1.3 × R IV+V……17
17 Dorsal abdominal pigmentation often consisting of segmentally arranged and variably developed but well-defined transverse black bars. Short-haired; longest hairs on ANT III less than 20 μm long…..Sitobion africanum
Dorsal abdominal pigmentation variably developed, ill-defined and not segmentally divided. Longest hairs on ANT III more than 20μm long…..Sitobion miscanthi
18ANT III with 1-4 small rhinaria near base (rarely one side has none). ANT tubercles well developed, extending forward much further than middle of head in dorsal view. SIPH pale …..19
ANT III without rhinaria. ANT tubercles small or only moderately developed, not extending forward much further than middle of head in dorsal view. SIPH dark or pale with dark apices…..20
19ANT with each segment pale at base and dusky/dark at apex (base of VI paler than apex of V). R IV+V 0.55-0.71 × HT II. (Al. without dorsal abdominal pigmentation) …..Metopolophium dirhodum
ANT progressively darker from base to apex. R IV+V 0.71-0.90 × HT II. (Al. with dark dorsal abdominal bars) …..Metopolophium festucae
20SIPH clavate. Dorsal cuticle ornamented with a pattern of rounded bead-like spicules, arranged in polygons…..Rhopalosiphum nymphaeae
SIPH tapering or somewhat thickened distally, but not clavate. Dorsal cuticle smooth or variously sculptured…..21
21SIPH black, swollen slightly on basal half (calf-shaped), contrasting with long (0.16-0.26 mm) pale cauda, which bears 4 hairs on middle part …..Hysteroneura setariae
SIPH pale with dark apices or entirely dark; cylindrical or tapering without any swelling of basal half. Cauda pale, dusky or dark, with 4-24 hairs…..22
22 SIPH pale basally, dark towards apices…..23
SIPH uniformly dark…..25
23SIPH 2.8-3.7 × longer than their width at midlength. ANT with primary rhinaria on ANT V much smaller than that on VI, its diameter 0.3-0.4 × width of segment at that point. R IV+V 0.85-1.0 × HT II…..Schizaphis minuta
SIPH 4.2-9.2 × longer than their width at midlength. ANT with primary rhinarium on ANT V about the same size as that on VI, its diameter more than 0.5 of width of segment at that point. R IV+V 0.65-0.8 × HT II…..24
24SIPH 3.1-3.7 × HT II, 0.19-0.25 × BL and 1.67-2.25 × cauda …..Schizaphis hypersiphonata
SIPH 1.8-2.9 × HT II, 0.11-0.19 × BL and 1.3-1.7 × cauda …..Schizaphis graminum
25 SIPH cylindrical or slightly swollen on distal half, with a smooth subapical constricted area before a well-developed flange. Dorsal cuticle with a reticulate pattern of spicules arranged in polygons, each polygon enclosing one or more additional spicules …..Rhopalosiphum padi
SIPH tapering from base to flange, without a subapical constriction. Dorsal cuticle with or without a reticulate pattern but not as above…..26
26ANT III-VI dark except for basal part of III. ANT PT/BASE 4.2-6.0. SIPH 1.6-3.3 × cauda. (Al. with media once-branched)…..27
ANT III and IV mainly pale, V dark towards apex, VI mainly dark. ANT PT/BASE 1.7-4.0. SIPH 0.8-2.0 (-2.5) × cauda. (Al. with media twice-branched)…..30
27ABD TERG 8 with 5-7 hairs. Longest hairs on ANT III 1.6-2.2 × BD III …..Schizaphis sp. near acori (Japan, BMNH colln)
ABD TERG 8 with 2 hairs. Longest hairs on ANT III 0.5-0.9 × BD III …..28
28 SIPH 2.2-3.3 × cauda. Longest hairs on hind femur shorter than trochantro-femoral suture. (Al. with sec. rhin. III 6-12, IV 2-6, V 0-2)…..Schizaphis rotundiventris
SIPH 1.6-2.4 × cauda. Longest hairs on hind femur as long as or longer than trochantro-femoral suture. (Al. with sec. rhin. III 15-29, IV 7-15, V 0-5)…..29
29 ANT I and II dark like most of ANT flagellum, only base of ANT III often pale. Cauda dark …..Schizaphis pyri
ANT I and II pale like base of ANT III. Cauda pale/dusky …..Schizaphis piricola
30 Cauda black with 11-27 hairs. Dorsal abdomen with black bands on ABD TERG 7 and 8. Longest hair on ANT III 0.8-3.4 × BD III…..Aphis fabae
Cauda pale or dusky with 4-8 hairs. Dorsal abdomen without dark markings. Longest hair on ANT III 0.4-0.7 × BD III….. Aphis gossypii
31 Eyes multifacetted. Distal part of cauda developed as a knob…..32
Eyes with only three facets. Cauda broadly rounded, not developed…..37
32Dorsal hairs long and spine-like. Eyes with an ocular tubercle. Anal plate either entire or with a shallow cleft (emarginate)…..33
Dorsal hairs mostly short with pointed apices or fan- or mushroom-shaped, or if long then rod-shaped or with expanded apices. Eyes protruding. and without an ocular tubercle (triommatidium). Anal plate bilobed, with a deep cleft between the two lobes …..34
33Dorsal cuticle uniformly sclerotic, adorned with small denticles or spinules between the hairs; intersegmental muscle sclerites not evident…..Sipha glyceriae
Dorsal cuticle not markedly sclerotic nor adorned with denticles; often showing dark inter-segmental muscle sclerites…..Sipha flava
34Fore and mid tibiae thickened at base, forming a smooth sclerotic “patella” (clearly different from base of hind tibia). SIPH stump-shaped, conical or raised pores…..35
Fore and mid tibiae constricted at base like hind tibiae. SIPH as slightly raised pores…..36
35Head pale. ABD TERG 8 with a pair of large quadrate processes each bearing two long rod-shaped slightly capitate hairs arising from tuberculate bases (Fig. 18k) …..Saltusaphis scirpus group
Head dark. ABD TERG 8 with variably developed hair-bearing conical processes, not longer than their basal widths (Note: a more complete key to sedge-feeding Saltusaphidinae can be found under Carex.)…..Nevskya fungifera
36ANT III 0.35-0.5 × head width across (and including) eyes. Posterior margin of ABD TERG 8 very evenly rounded (semi-circular) …..Allaphis ossiannilssoni group
ANT III 0.95-1.25 × head width across eyes. Posterior margin of ABD TERG 8 not very evenly rounded (Note: a more complete key to sedge-feeding Saltusaphidinae can be found under Carex.)…..Allaphis cyperi group
37 Tarsi 1-segmented. SIPH present as small pigmented cones. Facetted wax glands present …..38
Tarsi 2-segmented. SIPH absent. Anal plate enlarged and displaced dorsally. No facetted wax glands…..40
38R IV+V less than 0.15 mm, less than 1.8 × HT…..Tetraneura akinire
R IV+V more than 0.15 mm long, more than 1.8 × HT…..39
39 Body and ANT with numerous hairs of varying size and length …..Tetraneura radicicola
Body and ANT hairs all short, sparse and inconspicuous …..Tetraneura africana
40 Primary rhinarium on ANT V with plain rim…..41
Primary rhinarium on ANT V with fimbriate rim…..43
41ANT II about twice as long as ANT I, and nearly as long as ANT III. Anal plate displaced dorsally…..Smynthurodes betae
ANT II only a little longer than ANT I, and much shorter than ANT III. Anal plate in the normal posterioventral position…..42
42Primary rhinarium on ANT BASE V very large, transversely oblong and extending around segment, 4-5 × larger than primary rhinarium on ANT IV …..Forda formicaria
Primary rhinarium on ANT BASE V almost circular and less than 2 × larger than that on ANT IV…..Forda hirsuta
43Anal plate with numerous short hairs…..Geoica utricularia
Anal plate with 2 longitudinal rows of long hairs…..Geoica lucifuga
CyphomandraSolanaceae
Cyphomandra betacea Aphis craccivora, fabae, gossypii, spiraecola,
[Aphis sp. (Millar 1994)];
Brachycaudus helichrysi; Macrosiphum euphorbiae;
Myzus ornatus, persicae
C. clavataAphis citricidus, craccivora, fabae, odinae, solanella,
spiraecola;
Myzus ornatus, persicae

Use key to polyphagous aphids.

CyphostemmaVitaceae
Cyphostemma adenocaule Aphis gossypii
CypripediumOrchidaceae
Cypripedium spp.Aphis gossypii; Cerataphis orchidearum;
[Micromyzodium filicium]; Rhopalosiphum nymphaeae;
Sitobion luteum

Use key to apterae of orchid-feeding aphids under Cymbidium.

Cyrilla Cyrillaceae
Cyrilla racemiflora Aphis aurantii, iteae, nigra
1SIPH only about twice as long as wide, less than 0.7 × cauda …..Aphis nigra*
SIPH 0.9-2.3 × cauda…..2
2Stridulatory apparatus present (cuticular ridges of abdominal sternites 5 and 6 and a row of peg-like hairs on hind tibiae; fig. 122). SIPH 0.9-1.3 × cauda, which bears 10-26 hairs. Apices of tibiae normal…..Aphis (Toxoptera) aurantii
No stridulatory apparatus. SIPH more than 2 × cauda, which is about as long as its basal width, and bears c. 10 hairs. Apices of tibiae with a rounded knob-like structure ….. Aphis iteae
CyrtanthusAmaryllidaceae
Cyrtanthus sp.Myzus persicae
CyrtococcumPoaceae
Cyrtococcum accrescens Pseudoregma panicola
C. patens Pseudoregma panicola
C. trigonumPseudoregma panicola
CyrtomiumDryopteridaceae
Cyrtomium falcatum [Cyrtomophorodon cyrtomophitum];
Idiopterus nephrelepidis; Macromyzus woodwardiae
Neomyzus circumflexus
Cyrtomium sp. [Cerataphis lataniae – Swain 1919, 164]

Use key to fern-feeding aphids under Polypodium.

CyrtopodiumOrchidaceae
Cyrtopodium sp.Cerataphis orchidearum
Cyrtospadix see CaladiumAraceae
CyrtospermaAraceae
Cyrtosperma sp.Pentalonia caladii
CystopterisWoodsiaceae
Cystopteris bulbifera Macrosiphum cystopteris; Papulaphis sleesmanni
C. crispa (?)Taiwanomyzus alpicola
C. fragilisMacrosiphum dryopteridis; Taiwanomyzus alpicola
C. montanaAmphorophora ampullata;
[Rhopalosiphoninus staphyleae]
Cystopteris sp.Macrosiphum walkeri

Use key to fern-feeding aphids under Polypodium.

Cystostemon (including Vaupelia)Boraginaceae
Cystostemon sp.Aphis craccivora
CytisophyllumFabaceae
Cytisophyllum sessilifolium Acyrthosiphon parvum
Cytisus (including Sarothamnus, Spartocytisus) Fabaceae
Cytisus adamiiAphis cytisorum
C. albus Acyrthosiphon [loti], parvum; Aphis cytisorum
C. austriacusAcyrthosiphon parvum, pisum;
Aphis cytisorum, pseudocytisorum
C. austriacus ssp. heuffelii Aphis cytisorum; Ctenocallis dobrovljanskyi
C. battandieri = Argyrocytisus battandieri
C. beaniiMyzus cymbalariae
C. borysthenicusCtenocallis dobrovljanskyi
C. canariensis = Genista canariensis
C. candicans = Genista monspessulana
C. capitatus =C. hirsutus
C. elongatus[Acyrthosiphon caraganae]
C. graniticus Aphis cytisorum
C. heuffelii = C. austriacus ssp. heuffelii
C. hirsutusAcyrthosiphum parvum; Aphis cytisorum, zweigelti;
Ctenocallis dobrovljanskyi
C. multiflorus[Acyrthosiphon loti]; Aphis cytisorum ssp. sarothamni
C. nigricans = Lembotropis nigricans
C. nubigenus = C. supranubius
C. oromediterraneus = Genista balansae ssp. europaea
C. pilosus = Genista pilosa
C. procumbensAcyrthosiphon parvum, pisum ssp. spartii
C. proliferus Aphis cytisorum; Brachycaudus helichrysi
C. purgansAphis cytisorum ssp. sarothamni
C. ratisbonensis Acyrthosiphon parvum, pisum; Ctenocallis dobrovljanskyi
C. rhodopeus see Genista lydia
C. ruthenicus (incl. var. zingeri) Acyrthosiphon pisum; Aphis cytisorum
C. scopariusAcyrthosiphon caraganae ssp. occidentale, parvum, pisum;
Aphis craccivora, cytisorum ssp. sarothamni;
Aulacorthum solani; Ctenocallis setosa;
[Eriosoma sparthani (Boisduval – nomen dubium)];
Myzus persicae; Neomyzus circumflexus;
[Therioaphis trifolii]; [Trama troglodytes]
C. sessilifoliusAphis cytisorum, pseudocytisorum;
Acyrthosiphon parvum, pisum, [loti]
C. spinosusAcyrthosiphon parvum; [Ctenocallis israelica]
C. striatusAcyrthosiphon pisum; Aphis cytisorum
C. supinus = Cytisus hirsutus
C. supranubiusAcyrthosiphon [genistae], pisum, supranubius;
Aphis craccivora, cytisorum
C. villosusAcyrthosiphon parvum; Aphis craccivora, cytisorum;
Ctenocallis setosa
Cytisus sp.[Aphis genistae]

Key to apterae on Cytisus:-

1Body with a complete segmental series of long finger-like marginal processes. Cauda knobbed…..2
Body without long marginal processes. Cauda not knobbed…..3
2Dorsum with a complete series of pairs of long finger-like spinal processes, like the marginal ones…..Ctenocallis setosa
Dorsum without long finger-like spinal processes …..Ctenocallis dobrovljanskyi
3 Cauda helmet-shaped, not longer than its basal width in dorsal view. SIPH smooth, short, conical, with a subapical annular incision…..Brachycaudus helichrysi
Cauda tongue- or finger-shaped, much longer than its basal width. SIPH imbricated, tubular, without a subapical annular incision…..4
4 ANT tubercles undeveloped or weakly developed. ABD TERG 1 and 7 with marginal tubercles (MTu). SIPH dark…..5
ANT tubercles well developed. ABD TERG 1 and 7 without MTu. SIPH pale or dark …..9
5 Dorsal abdomen without any dark reticulated sclerites. Cauda pale or dusky, usually paler than SIPH…..Aphis gossypii
Dorsum usually with a black sclerotic shield, which under the microscope has a distinct pale reticulation that follows the reticulate sculpturing of the cuticle; sometimes this shield is reduced of fragmented (especially in small specimens developing at higher temperatures), but there are usually at least some small fragments showing a reticulate pattern. SIPH and cauda both black…..6
6R IV+V more than 3 × longer than its basal width, and 1.2-1.3 × HT II …..Aphis zweigelti
R IV+V less than 3 × longer than its basal width, and 0.9-1.3 × HT II…..7
7 SIPH 0.9-1.2 (-1.3) × cauda. R IV+V 1.0-1.15 × HT II. Dorsal pigmentation often reduced to small scattered sclerites…..Aphis pseudocytisorum
SIPH 1.2-2.2 × cauda (rarely less than 1.3). R IV+V 0.9-1.3 × HT II. Dorsal abdomen usually with a dark shield, rarely with scattered small sclerites except in summer dwarfs …..8
8R IV+V 0.88-1.16 × HT II (mostly 0.9-1.05 X). Anterior half of genital plate with 2 (-3) hairs…..Aphis craccivora
– R IV+V 0.97-1.3 × HT II (mostly 1.06-1.2 X). Anterior half of genital plate with 2-8 hairs (mode 4, mean 5.2)…..Aphis cytisorum (incl. ssp. sarothamni)
9 Head spiculose with inner faces of ANT tubercles steep-sided, almost parallel or apically convergent…..go to key to polyphagous aphids, starting at couplet 5
Head smooth with inner faces of ANT tubercles divergent…..10
10 ANT VI BASE at least 2 × R IV+V. SIPH very attenuate; thinner at midlength than hind tibia at its midlength. Cauda very thick on basal half, but tapering distally almost to a point; with 8-14 hairs …..Acyrthosiphon pisum
ANT VI BASE less than 2 × R IV+V. SIPH as thick as or thicker than hind tibia at their respective midlength points. Cauda tapering to a rounded apex, and bearing 6-16 hairs…..11
11BL 5.0-6.1 × SIPH. ANT PT/BASE 5.3-6.9. Cauda bearing (8-)10-16 hairs…..Acyrthosiphon supranubius
BL 3.1-4.2 × SIPH. ANT PT/BASE 2.9-5.4. Cauda bearing 6-10 hairs …..12
12ANT PT/BASE 2.9-4.0. R IV+V 0.70-0.84 × HT II. BL 2.6-4.3 mm…..Acyrthosiphon caraganae
ANT PT/BASE 4.3-5.3. R IV+V 0.88-1.05 × HT II. BL 1.9-2.5 mm…..Acyrthosiphon parvum