184 APHIDS OF THE ROCKY MOUNTAIN REGION 
This species differs slightly from the original description of A. varians in 
slightly smaller number of sensoria in the antenna of alate vivipara. The resem- 
blance to A. oenotherae is very close. However, cornicle in alata vivipara of 
A. oenotherae is usually shorter than unguis while in A. varians cornicle is 
usually longer than unguis. The difference of host makes it seem best not to 
pronounce the two forms as identical without experimental biological work. 
The description of A. grossulariae Kaltenbach agrees in all particulars men- 
tioned except Kaltenbach’s statement that “cornicles are one-half to two-thirds 
normal length.” 
Aphis viburnicola Gillette 
The Snowball Aphid 
Aphis viburnicola Gillette, 1909b:280; Gillette and Bragg 1915a:102 and 1918b:329; 
Gillette and Palmer, 1932b:452. 
Fundatrix. First Instar. Apparently ashy gray, but really pale greenish yellow, heavily 
covered with powder, with four rows of black dots; cornicle hardly elevated, appearing as a 
double ring; head, and appendages dusky brown. Young Adult. Light green; covered with 
powder; distal half to entire antenna, cornicle, cauda, anal and genital plates and entire 
tibiae and tarsi and tip of rostrum dusky to black. Old Adult. Deep green; covered with pow- 
der. Size 2.50-3 by 1.5; hind tibia .90; antenna .90, III and IV coalesced; hind tibia not notice- 
ably swollen but bearing a few sensoria. 
Fundatryx 
re’ . 14 
A 7 4 CD pation SEI 
Alate = Apt. 
Fig. 212. Aphis viburnicola 
Alate Vivipara. Newborn. Pale greenish yellow to very pale yellow; covered with white 
powder, not showing black spots as in young fundatrix. Adult Spring Migrant. Head and 
thorax black; abdomen pale greenish yellow with dusky to blackish green lateral areas and 
dorsal bands, the latter coalesced on abdominal II to VIII; appendages, cornicle, rostrum and 
anal and genital plates dusky to black; cauda pale to dusky. Body length 2.5-2.7; hind tibia 
1.25; antenna 1.2-1.6, secondary sensoria large, subcircular, tuberculate; rostrum obtuse, barely 
attaining 3d coxa. Antenna rather stout, as wide or wider than hind tibia; base of VI abruptly 
constricted to unguis. Hairs pointed, rather drooping, numerous. Cornicle cylindrical or 
slightly tapering, with flange and with denticulate, very closely placed imbrications. Cauda 
tapering, acute, about as broad as long and bearing 3 hairs on each side. Hind tibia of spring 
migrants swollen on distal half which portion bears about 20 sensoria. Lateral tubercles 
distinct. A pair of dorsal tubercles present on abdominal VIII. Fall Migrant. Same as spring 
migrant except as follows: Abdomen rusty brown instead of pale, with dark bands on II to 
VIII and hind tibia not noticeably swollen but usually bearing a few sensoria. 
Ovipara. Nymph and Young Adult. Pale yellow; covered with white powder; later 
becoming sordid yellow. Older Adult. Apterous. Salmon-pink, mottled with brownish with 
eggs showing through dorsal body wall; appendages pale to light brownish. Body length 
1.50-1.80; hind tibia .40; antenna .45-.50, III and IV coalesced; hind tibia distinctly swollen 
along entire length and bearing numerous sensoria. 
Male. Alate. Head and thorax black; abdomen rusty brown, with lateral areas, blotch 
behind cornicle, and narrow dorsal bands dusky; antenna, tibiae, anal and genital plates and 
cornicle black; cauda dusky. Body length 1.8-2; hind tibia .55; antenna 1.40-1.60, segments 
thick .06 in diameter, broader than hind tibia. 
Egg. Newly laid, pale yellow; later, black; shining. Size .66 by .20. 
