AMERICAN OOLKOPTERA. 31 



elytra being more broadly oval, others are more slender and always 

 smaller. The former I find to have a smooth head and the mandibles 

 very decidedly sometimes rather deeply notched. Both the above 

 characters are somewhat variable but hold good with the majority of 

 specimens, aad they appear to me to be sexual. 



CHILOMETOPOM, n. gen. 



Body winged, elongate oval. Front trilobed, middle lobe promi- 

 nent, trapezoidal, feebly clasped by the mandibles and entirely con- 

 cealing the labrum. Eyes with superciliary ridge, prominent and 

 coarsely granulated. Antennae longer than head and thorax, slender, 

 joints 8—10 somewhat broader, last joint equal to (heJopioides) or 

 longer Qibnonne) than the preceding. Mentu.n transversely hexago- 

 nal, large, anterior angles rounded. Maxillary palpi with last joint 

 elongate triangular. Prosternuin not produced behind. Legs slen- 

 der, anterior tibiae slender without apical prolongation, tirsi sparsely 

 clothed with short spines, hind tarsi moderately elongate, first joint 

 equal to the third and fourth together. 



Two species before me agree in the possession of the above cha- 

 racters. 



The genus is referred to Epifragini from the form of the front and 

 the elongate metasternum. In both species the thorax is somewhat 

 narrower than the elytra, although not more so than in some of our Epi- 

 trayus. The vestiture of the tarsi is nearly as stiff and spinose as in 

 Triorophua, The middle lobe of the front is very prominent, truncate 

 in helnpioides, and oval at tip in abnarme, the surface being flat in 

 the former and moderately convex in the latter. Regarding the 

 affinities of this genus with foreign genera I express no opinion ; from 

 our own genera of the tribe it is easily known, the tarsal vestiture and 

 superciliary ridge at once distinguish it from Schoenicus, with which 

 alone it could be founded. The two species are : — 



C. abnorme, Horn {Triv.ytis), Trans. Am. Phil. Soc. 1870, p. 261.— Thorax 

 narrower at base than apex. Las joint of antennae as long as the two preced- 

 ing together. Length .26 inch; 6.5 mm. 



Collected in Nevada. Cabinet of Dr. Leconte. 



C'. helopioirtes, n sp. — Castaneous, shining, form oblong oval. Head 

 broadly oval. Mandibles and clypeus coarsely and densely punctured, vertex 

 and occiput much more sparsely. Thorax nearly twice as wide as long, apex 

 feebly emarginate, anterior angles acute and very slightly everted, base 

 broadly rounded at middle, feebly sinuate each side, hind angles subacute but 

 not prominent, sides moderately arcuate and slightly divergent to base. Ely- 

 tra slightly broader at base than thorax, elongate oval, aides moderately arcu- 



