170 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



tlie anteiiiial Joints, and ciliated. Pa]])i large and stont, ascending, curving- np in front of the 

 clypeus, and re:icliing well beyond the front of the head; the hairs beneiith thick and spreading; 

 third joint small, conical. IMaxilhe short, not reaching out to the paljii. Thorax with a high 

 pointed median tiitt, slojiing behind. 



Fore wings a little less than one-half as broad as long; costa convex, esi)ecially toward the 

 apex, which is rounded; outer edge oblique, slightly convex to the internal edge. Venation: A 

 long narrow subcostal cell; second and third subcostal ^•enules unusually shoit, the ajncal space 

 between the costa and subcostal vein being very narrow; in this respec't the genus is much as in 

 Lophodonta (especially L. hnsitriens); the third subcostal venule is oue-half as long as the second. 

 The venation is otherwise as in Notodouta, the discal veins being the same, and vein VI looped at 

 base, as in Notodonta. 



The genus differs from Notodonta in having no tuft on the inner edge. The hind wings differ 

 from those of Notodonta in being shorter and rounder and in the apex being more produced, 

 while the venation differs in tlie costal vein being longer and turned up at the end on the costa; 

 otherwise the venation is much as in Notodonta. 



The legs are much as in Notodonta, being rather slender, the femora and tibiae densely pilose, 

 the latter with moderately large tibial spines. Abdomen blunt at the end, with a small anal tuft. 



Coloration : The only North American species is whitish gray, witli brown between the cubital 

 vein and the costa, sending two prominent teeth toward the internal edge. There are no 

 transverse lines of any sort. The hind wings ai'e chocolate-brown. 



This genus is distinguished by the antenme being pectinated to the end, and with longer 

 branches than in Notodonta; by the large palpi extending well in front of the head; especially by 

 the high prominent median thoracic tuft, and by the well-rounded apex of the fore wings. It 

 differs from Notodonta not only in the more broadly iiectinated antenna^ l)ut in the much longer 

 pal))! and the squarer fore wings, the outer c<lge being less oblique, while the internal edge is 

 sim])le, not bearing a tuft. The hind wings are also a little shorter and more rounded at the apex 

 than iu Notodonta. 



Larva. — The larva differs from that of Notodonta, or anj' other genus of the family, in the 

 abdominal segments being nearly all i)rovided with a dorsal hunix), the abdominal segments 1 to S 

 having each a "large anteriorly directed prondnence ending in a bifid ridge, the incision being 

 transverse, the anterior portion being curved backward and larger than the posterior part, the 

 two looking very nuich like the bill of an eagle, and susceptible of being opened and closed." 

 (Marlatt.) It is silvery green, with dark bluish green subdorsal and lilaceous lines on the thoracic 

 segments. It is evidently adapted for i)rotectiou while feeding on the edge of an elm leaf, the 

 serrations of the body resembling those of the edge of the leaf of its food plant. 



Pupa. — Body rather stout, somewhat pointed at the end, which bears an unusually long, 

 slender, smooth, round cremaster, armed with very short curled set;Ti, and ends in two up curved 

 slender, hooks. The surface of the body with shallow and sparse ]iits; on the .sutures of the 

 abdominal segments very finely shagreened. 



Cocoon. — Formed of thick, brownish silk, situated within folded leaves or under some slight 

 protection at the surface of the soil. Concealed by particles of earth. (Marlatt). 



Geographical distribution. — Besides a single si)ecies inhabiting the Atlantic and Central 

 States of North America, iiududing Kansas, Walker describes a species {X. pallida) from Nepaul, 

 and Oberthur describes and figures V. davidi from the north of China, which is very similar to 

 our bidentata. The genus is not represented in western Asia, southern India, or iu Europe. 



