202 TRANSACTIONS OF THE ILLINOIS 



the mass of eggs adhering to the leaf, thus showing a close relation to the 

 CoccidcE, or bark-lice. But on the other hand, the winged individuals 

 possess four wings instead of two, which character places them among 

 the Aphides. The further character will be found in the following specific 

 characters of this species. The winged individuals, black, 0.08 inch in 

 length to the tip of the abdomen, 0.12 inch to the tips of the wings ; ab- 

 domen, dusky-red and slightly covered with down ; the wings, dusky and 

 grayish ; the rib-vein of the fore wings runs straight to the outer margin 

 forward of the tip, and gives off from its middle, on the outer side, a very 

 oblique branch which runs to the outer margin, its tip producing a slight 

 angular projection of the margin ; on the inner side of the rib-vein there 

 are three branches or discoidal vains, all simple, the third running to the 

 tip of the wing. The hind wings have an angular point on the outer or 

 front margin ; the rib-vein sending off one branch ; antennae short, thread- 

 like, and four or five jointed. 



Found during the summer stationary upon pine leaves. 



103. Chermes laricifolice, Fitch. The Larch Chermes, 



Similar to the preceding species; but found on the leaves of the 

 American larch or tamarack. Shining black, o.io of an inch long; abdo- 

 men, dark green ; legs, pale or whitish; wings, nearly hyaline, with pale 

 brown veins; the large stigma, opake and pale green. 



CONCLUDING REMARKS. 



As I have already given somewhat fully the general history of the 

 Aphides, including an account of their singular mode of reproduction, 

 also the methods adopted or that I had to suggest for their extermination, 

 I will only add here some general remarks in reference to points not fully 

 given, and some facts in reference to their history and operations in 

 European countries where they have been more thoroughly studied than 

 here. 



Although most cultivated as well as uncultivated plants are more or 

 less subject to the attacks of one or more species of plant-lice, yet in 

 England, and I believe so far as observed in this country, clover appears 

 to be singularly exempt. The potato, which is subject to the attacks of 

 so many other insects, appears to have no plant-louse peculiar to it ; 

 occasionally it is attacked by the Bean Aphis, and some other species, 

 sometimes, though very rarely in abundance. But even when this hap- 

 pens, they appear to do but little injury to the top and none to the tuber, 

 their attacks having, as has been shown, nothing whatever to do with the 

 rot. Curtis states that in 1847, when the Aphides were abundant in 

 certain parts of England, destroying the bean crop, potatoes in the same 

 gardens were not injured. Harris speaks of plant-lice which sometimes 

 infest potato fields, but I suppose he alludes to the occasional visitations 

 I have mentioned. 



In this country the apple, cherry, currant, hickory, willow, grape, 

 cabbage and a few other vegetables appear to suffer most from the attacks 



