AMERICAN COLEOPTERA. 309 



THAIiYCRA Erichs. 



Labrum feebly visible, bilobed. Front at middle prolonged, the 

 sides parallel, truncate in front. Antennae with abrupt three-jointed 

 club, no antennal grooves distinctly defined. Mandibles simple at tip, 

 a small tooth behind the apex. Prosternum elevated, subeonieal and 

 slightly prolonged at tip, not laminiforni, mesosternum not carinate. 

 Anterior tibiae triangularly dilated, the outer apical angle dentiform, 

 middle and posterior spinulose externally and at tip. Anterior tarsi 

 dilated, the middle a little broadened, the posterior slender. Claws 

 simple. Elytra entire. 



The males have a very distinct additional dorsal segment. 



This genus differs from all our genera of the present tribe (except- 

 ing PerthaJycra), by the absence of antennal grooves, and from the 

 latter by the form of the anterior tibiae and the tarsi. The structure 

 of the prosternum is radically different from that of Mdigethes and 

 the mesosternum is without carina. 



One species only is known in our fauna. 



T. concolor Lee. — Oblong oval, rufo-ferruginous, moderately shining, 

 sparsely pubescent. Head and thorax moderately densely punctate. Thorax 

 twice as wide as long, narrower in front, base arcuate, apex feebly emarginate, 

 sides feebly arcuate, margin very narrow, f3nely fimbriate, hind angles obtusely 

 rectangular, disc convex. Elytra as broad as the thorax, about one-fourth 

 longer than wide, sides and apex arcuate, surface as coarsely punctured as the 

 thorax but less densely, the punctures becoming rapidly finer and finally near 

 the apex obsolete. Prosternum very sparsely finely punctate. Mesosternum 

 and abdomen coarsely and moderately densely punctate. Length .14 inch ; 

 3.6 mm. 



I have seen but one male specimen, collected by Dr. Leconte, on 

 the north shore of Lake Superior. 



PERTHAL,YCRA n. g. 



Labrum moderately prominent, bilobed. Epistoma at middle slightly 

 prolonged. Mandibles acute at tip, a small tooth behind the tip. 

 Mentum transverse, longest at middle. Last joint of maxillary palpi 

 conical obtuse, labial ovate, slightly compressed and truncate. An- 

 tennae rather short, club broadly oval, three-jointed, last joint small 

 retracted, grooves very feebly marked, strongly convergent. Pro- 

 sternum convex between the coxae, the tip obtusely prolonged. An- 

 terior tibiae triangular, the apical angle prolonged, the apical margin 

 posteriorly dentate, outer edge bidentate at middle, middle and pos- 

 terior tibiae strongly spinulose. Tarsi slender, the anterior dilated in 

 the male only. Claws simple. 



The m lies have an additional segment and the anterior tarsi dilated. 



