398 APHIDS OF THE ROCKY MOUNTAIN REGION 
E.—Cornicle shorter than twice hind tarsal II. (p. 167).............. Aphis ribiensis 
EE.—Cornicle 2 or 3 times length of hind tarsal IT. 
F.—III shorter than unguis. (p. 168)............--::s-ssssce-seses Aphis ribi-gillettei 
FF.—III not shorter than unguis. 
G.—Alata with sensoria absent on V; hairs short, on appendages, 
not as long as diameter of segment bearing them. (p. 156)............ 
Se ie A The New Mexico Gooseberry Aphid (Aphis neomexicana) 
GG.—Alata with sensoria present on V; hairs on appendages as 
long as diameter of segment bearing them. (p. 183)............----..-.------ 
sleet etl gen petane nh ene cee Bae The Variable Currant Aphid (Aphis varians) 
Dahlia (Dahlia sp.) 
A.—Body black; cornicle about twice as long as hind tarsal II, imbricated, without 
abrupt encircling depression next to flange; cauda bushy, with 6 or 7 hairs on each 
side; longer than wide and spoon-shaped. (p. 135)................ The Bean Aphid (Aphis fabae) 
AA.—Body pale green, alata with black dorsal patch on abdomen; cornicle 1 to 1.5 
times as long as hind tarsal II, smooth, with abrupt encircling depression next to 
flange; cauda not bushy, with only 2 or 3 hairs on a side, broad; hardly longer than 
wide, slightly tapering. (p. 142)............-.......--.. The Leaf-curl Plum Aphid (Aphis helichrysi) 
Dandelion (Taraxacum officinale) 
A.—Living above ground. 
B.—Body dark red-brown, appearing black; appendages black; frontal tubercles 
developed beyond vertex; antenna about as long as body; cornicle as long as 
III, reticulated distally; sensoria in alata numerous on III, none on IV or V. 
(5832.6 )5 cee ee aren eee eres The Dark Dandelion Aphid (Macrosiphum taraxaci) 
BB.—Body pale to medium green, often with dusky dashes; appendages dusky 
yellow; frontal tubercles not developed beyond vertex; antenna shorter than 
body; cornicle shorter than III, not reticulated; sensoria 10 to 16 on III, usually 
present on IV and V. (p. 123)......The Western Aster Root Aphid (Aphis armoraciae) 
AA.—Living on roots under ground. 
B.—Hind tarsal II nearly as long as hind tibia, twice length of III; media of fore 
wing faint, once-branched. (p. 000)....The Long-footed Dandelion Aphid (Trama rara) 
BB.—Hind tarsal II much shorter than hind tibia, shorter than twice length of 
III; media of fore wing either simple or twice-branched, not faint. 
C.—Media of fore wing simple; cornicle absent; sensoria narrow-transverse; 
cauda semi-lunar? (p.1367) s222 2k Renn pas ca scnceteat cadence nee 
oe eee en erate mete te een The White Aster-root Aphid (Prociphilus erigeronensis) 
CC.—Media of fore wing twice-branched; cornicle cylindrical, at least as 
long as hind tarsal II; sensoria subcircular; cauda at least as long as wide. 
D.—Hairs on appendages reclinate, not numerous, shorter than diameter 
of the segment bearing them; sensoria 10 to 16 on III of alata. (p. 123) 
Sere en Regen Se Sa, Seen The Western Aster-root Aphid (Aphis armoraciae) 
DD.—Hairs on appendages nearly erect, numerous, at least as long as 
diameter of segment bearing them; sensoria 20 to 24 on III of alata. 
(p.°146 2 Eee ee En Cee eee ee gee ig ee Aphis knowltoni 
Dogwood (Cornus stolonifera) 
A.—Alata black except anterior segments of abdomen which are white; media of fore 
wing once-branched; cornicle hardly evident, on low cone. (p. 12)..........2::-2:cceeecceeeeeeeeeees 
AMEE RD AUR Se AM ED oP aeeeesreesseereeeceeeeeee DL HE White-banded Dogwood Aphid (Anoecia querci) 
AA.—Alata not colored as above; media of fore wing twice-branched; cornicle plainly 
evident, elongate. 
B.—Body yellow-green, mottled with darker green, with darker green band just 
anterior to cornicles; hairs inconspicuous, drooping. Absent from May 15 to 
August::(p. 141) 232 The Dogwood or Sunflower Aphid (Aphis helianthi) 
BB.—Body dark olive-green to blackish; hairs noticeable, erect, especially on 
tibiae of aptera. Present throughout the summer, alatae appearing middle of June. 
Cp5055) eee eee The Dark Green Dogwood Aphid (Aphis neogillettei) 
Elderberry (Sambucus sp.) 
A.—Antenna shorter than body; frontal tubercles not developed to exceed vertex. 
B.—Cauda spoon-shaped; cornicle shorter than III, not longer than unguis; sen- 
soria 12 to 19 on III in alata. (p. 135) cc-ccccceccscccccccesacccosees The Bean Aphid (Aphis fabae) 
