INSECT ENEMIES OF EASTERN FORESTS Le 
FIELD KEY TO THE APHIDS, BASED PRINCIPALLY ON HOST PLANTS—Continued 
29 (19). Large species, etc.—Continued 
Birch: On twigs and leaves; 3 to 4 mm. long; color whitish to 
yellow, with or without black stripes on head and thorax and 
dark bands oa dorsum of abdomen_______ Calaphis (p. 129). 
On twigs and leaves: 2 to 3 mm. long; color light green, 
with or without dark patch on abdomen; hind tibiae pale 
with distal part and tarsi black or with dark brown 
STO Reed eh ce ge et, mean ek Se ey ee Euceraphis (p. 129). 
_Boxelder: On leaves and twigs; 2 to 2% mm. long; color yellow- 
ish green marked with brown on thorax and abdomen or with 
head, antennae, thoracic lobes, sternal plates, and cornicles 
black or yellowish to apple green; antennae rather hairy 
Pertphyllus (p. 129). 
Butternut: On leaves; 1% to 2 mm. long; color pale yellow, 
costal vein yellow or brown, or a brown band extending be- 
yond stigma; antennae ringed with brown__ Wonellia (p. 129). 
Dogwood: On leaves and twigs except during summer; about 
14% mm. long; head and thorax black, abdomen greenish 
with a pink tinge and a row of black spots on each side_---_- 
Anoecia (p. 127). 
Elm: Causing mottling or dropping of leaves; 1% to 2 mm. 
long; color green or greenish yellow, abdomen uniformly 
colored or spotted dusky______-__--_-._._Myzocallis (p. 129). 
Hawthorn: On branches and twigs in winter, leaves in spring; 
3 to 4 mm. long; abdomen green with black dots on each 
sidesheadeand. thorax-black_ = 5 =— = 22% Anuraphis (p. 129). 
Hickory: 
a. Large species, about 6 mm. long; mostly on branches and 
twigs; color ash gray with triangular spots on prono- 
tum covered with bluish-white pruinosity 
Longistigma (p. 127). 
aa. Smaller species, 144 to 2mm. long; occurring on leaves 
b. Causing mottling or dropping of leaves; color 
green or greenish yellow, abdomen uniformly 
colored or spotted dusky__-Myzocallis (p. 129). 
bb. Color pale yellow, costal vein yellow or brown or 
a brown band extending beyond stigma; an- 
tennae ringed with brown____ Monellia (p. 129). 
Linden: On underside of leaves; 2 to 3 mm. long; color yellow; 
antennae uniformly yellow or ringed with brown 
Therioaphis (p. 129). 
Maple: 
a. Color brownish, often covered with white flocculence. 
b. Without white flocculence; egg-laying females 
with 7th and 8th abdominal segments pro- 
longed into ovipositor_--Drepanaphis (p. 129). 
bb. Usually with white flocculence 
ec. Fourth antennal segment about one-half 
or less as long as third segment; length 
2 to 4 mm.; always with white floccu- 
lence on underside of leaves or on trunks 
Prociphilus (p. 132). 
ec. Fourth antennal segment at least two- 
thirds as long as third segment; length 
about 3 mm.; usually with white floccu- 
lence. On leaves and twigs of sugar 
MAPLE: a=" aa Neoprociphilus (p. 132). 
aa. Color not brownish; either yellowish, reddish, or shading 
ing to green 
d. Four alternatives: 
On soft maple leaves and twigs; 3 to 4 mm. 
long; color dusky reddish to dark yellowish 
preen sae ee aera = S Clavigerus (p. 129). 
792440°—49—_8 
