170 TRANSACTIONS OF THE ILLINOIS 



40. Aphis asclepiadis, Fitch. The Silk-weed Aphis. 



Inhabits the under surface of the leaves of the common Silk-weed. 

 Black ; abdomen pale green ; two rows of impressed dusky dots on each 

 side, three in the lower and five in the upper row ; honey-tubes nearly 

 reaching to the tip of the abdomen ; veins of the fore wings brown, the 

 costal or marginal one whitish; stigma smoky-white. Length, 0.15 inch. 



41. Aphis cornifoHce, Fitch. The Dogwood-leaf Aphis. 



Inhabits the under side of the leaves of the Dogwood (^Corniis pani- 

 culata). The apterous females are black, somewhat powdered or mealy, 

 and obovate in form ; legs pale yellow, feet black ; antennae pale yellow, 

 tips black ; honey-tubes nearly reaching the tip of the truncated abdomen. 

 Length, 0.05 inch to tip of the abdomen. 



42. Aphis cratcBgifolice, Y'ltch. The Thorn-leaf Aphis. 



Found on the leaves of the Thorn {CratcEgus punctata), which it 

 corrugates. Black; abdomen green, with a row of blackish dots along 

 each side; veins of the fore wings whitish, black at their tips; tibiae or 

 shanks, except at their tips, and base of the thighs, green ; honey-tubes 

 equaling nearly half the distance to the tip of the abdomen. Length, o. 15 

 inch. 



43. Aphis betul(Zcolens, Fitch. The Birch-inhabiting Aphis. 



Sulphur-yellow ; antennae deep black, except the two basal joints, 

 which are sulphur-yellow ; the following joints are white at their bases ; 

 nerves of the fore wings black, the costal sulphur-yellow, the base of the 

 forked vein hyaline ; stigma transparent yellow ; honey-tubes very short. 

 Length, 0.18 inch. 



44. Aphis aceris, Linn. The Maple-tree Aphis. 



Our species, which occurs on Acer Pennsylvanicum, appears to be 

 identical with the European species. 



45. Aphis sambucifolice, Y'xich. The Elder-leaf Aphis. 



Found on the under side of the leaves of the Elder. Black ; tibire 

 and base of the thighs pale ; veins of the fore wings black, the forked one 

 transparent at its base; the stigma dusky. ' Length, 0.15 inch. 



46. Aphis pinico lens, Fitch. The Pine-inhabiting Aphis. 



Found solitary on the Pine, Straw-yellow, densely covered with 

 Avhite powder; antennae black, bases pale, with a dusky ring; fore wings 

 with a fuscous spot on the tip of each vein ; veins brown, hyaline at their 

 bases, the costal one straw-yellow; honey-tubes very short. Length, 0.25 

 inch. This probably belongs to another genus. 



