198 



TRANSACTIONS OF THE ILLINOIS 



Males black, powdered; wings hyaline, with brown veins; legs 

 whitish, knees and feet black. Length, 0.09 inch. Larvae smaller and 

 brownish. 



This is placed by Dr. Fitch in the genus Brysocrypta, but appears to 

 be so closely related to other species here included in Pemphigus, I have 

 concluded to refer it to that genus for the present. It is possible that 

 further investigation will prove it and Hormaphis hamamelidis, here- 

 after described, to be identical, notwithstanding the apparent generic 

 differences. 



The wings are pellucid and colorless, as are the oblique or discoidal 

 veins ; the rib-vein blackish, coarse and somewhat enlarged along the 

 inner margin of the stigma ; marginal vein blackish. Length to the tip 

 of the abdomen, 0.05 of an inch; to the tip of the wings, 0.08. 



82. Thalaxes ulmicola, Fitch. The Cockscomb Elm-gall Louse. 



The genus to which this 



species 



belongs 



resembles 



Eriosoma in having the third 

 vein of the fore wings once 

 forked ; but the hind wings 

 differ in having but a single 

 branch or discoidal vein ; it 

 also differs in placing the 

 wings horizontally on the 

 back, in repose, instead of 

 erect. 



This species forms the 

 comb-shaped galls so com- 

 mon on the upper side of 

 the leaves of young white 

 elms. These galls are usually about an inch long, varying in height from 

 one to three-quarters of an inch ; compressed and grooved on the sides 

 and perpendicular, showing tooth-like conical projections at the top ; 

 opening by a long slit on the under side. The inside is wrinkled perpen- 

 dicularly into deep plaits, and occupied by one female and her projeny, 

 some of which may often be seen strolling out upon the under side of the 

 leaf. The young are quite small, oval and yellowish white, with blackish 

 legs; the mature wingless female is about 0.07 inch long, oval and pale 

 yellow, more or less coated above with white powder, legs and antennae 

 blackish. 



Fitch placed this species in the genus Byrsocrypta, but Mr. Walsh, 

 who had the good fortune to find some of the winged individuals, which 

 Dr. Fitch did not see, has shown that it belongs to Thelaxes. The winged 

 females, according to Walsh, are black and more or less primose. 



%Ty. Adelges abietes ? (Pack.) The Spruce Adelges. 



The genus to which this species belongs is distinguished by the broad 

 and flattened form of its species, which usually attack coniferous trees. 



