6o OHIO BIOLOGICAL SURVEY 



The dorsum is covered with comparatively large, though almost invisible spines 

 of the same color as the integument. The segmental bristles in this case are very 

 inconspicuous, only about three times as long as the integumental spines. The color 

 and vestiture are always very much obscured by a dusting of fine, white, powdery or 

 cotlonv material which the larvae derive from the gall-making aphides among which 

 they feed. This too, is partly responsible for the unusual opaqueness of the integu- 

 ment or the fact that none of the viscera show clearly. A slight darkening of the 

 posterior median line indicates the dorsal blood-vessel, but its outlines or pulsation 

 cannot be discerned. 



The antennae are unusual in having the two smaller segments, wdiich lie side by 

 side on a fleshy elevation and are usually rounded, considerably elongated in a vertical 

 direction, contiguous medially. 



The mouth-parts are strong, the V of the jaws short, \dth a long slender med- 

 ian, terminal projection; the spurs at the base of the lower jaw short. There are three 

 pairs of mouth-hooklets; two pairs close beside the jaws, the dorsal ones short triangular, 

 the ventral pair elongate; and a lateral or outer pair heavy, unequally bidentate, 

 recurved. The anterior spiracles are m.oderately elevated on a sub-conical prominence 

 and are guarded by six, unequal, tooth-like lobes. 



The posterior breathing appendages present the following characters: The spira- 

 cles are straight, moderately long, rather prominently raised above the general surface. 

 Dorsal spiracular spine median to the circular plate, wanting. Inter-spiracular 

 projections four on a side, bristle-like (in this respect difTering from all the other 

 larvae I have examined) the bristles one-half to one-third as long as the spiracles. 

 Surface between the spiracular elevations free from warts or ridges, depressed between 

 the outer ends of the spiracles. The sides of the tubes are finely and unevenly 

 echiiiulate; a ring-like constriction about mid-length beyond which the diameter is 

 slightly less to the tips, where the spiracles expand somewhat. 



These larvae were abundant, and apparently nearly full grown, on 

 June 17, near Lakeville, in Wayne Co., Ohio, when the material was col- 

 lected. They were found living in the galls on a .species of Elm (U//mis) 

 which are familiarly known from their shape as "Cock'.s-Comb-Galls," 

 preying upon the gall producing aphids, Colopha nlDn'cola which line the 

 inner walls of the gall chambers. 



The.se galls are formed on the upper surface of the leaves, opening 

 beneath thru a sht-like aperature, several to many obliquely arranged at 

 the sides of the mid-vein. They are commonly an inch in length by a 

 fourth or more in width, incompletely divided into a series of about half 

 a dozen chambers. The upper surface of the gall is dentate and gives to 

 the gall its name. 



Sometimes two or three of the larvae will be found in one gall, a 

 space four or five times the volume of their own bodies. These galls are 

 rigid, the edges of the .slit closely apposed and offering considerable resis- 

 tance to being opened. It therefore .seems very doubtful to me if a larva 

 ordinarily ever leaves the particular gall in which it begins its growth. 



