AMERICAN COLEOPTERA. 271 



feebly sinuate and the hind angles distinct, almost rectangular. In 

 C abdoniinah'fi this difference in the thorax is not evident. I am 

 not aware that any European species exhibits such sexual differ- 

 ences in the thorax, possibly they do not exist or such observers 

 as Erichsou and Duval would have noticed them, while Mr. Murray 

 appears to have described the sexes of one of our species under 

 two names. 



Cercus having simple claw:^ is allied to Amartus, but differs from 

 that and Antlionseus in having but one abdominal segment exposed, 

 and the elytra being very distinctly margined at the sides, the 

 epipleurae well defined. 



The species occurring in our fauna are as follows : 

 Antennse siinilar in the sexes. 



Club triarticulate; body above green or bluish glabrous.. ..abdomiiialis. 

 Club biarticulate; body above not metallic, pubescent. 



Elytra sparsely punctate, that is the distance between the punctures is 



greater than the size of the punctures peniiatus. 



Elytra densely punctate, punctures closer together than their own dia- 

 meter serieaus. 



Antennae dissimilar in the sexes, the first two joints dilated in the male. 



Elytra piceous with discoidal rufous spot on each bipusttllatllS. 



C abrtoilliiialis Erichs. — Oval, convex, metallic blue, shining, abdomen 

 and legs red. Head densely punctate. Antennae rufous, club piceous. Thorax 

 convex, one-third wider than long, base a little wider than apex, sides moder- 

 ately arcuate, feebly sinuate near the basal angles which are rectangular, 

 surface equally punctate, punctures moderately coarse not dense. Scutellum 

 sparsely punctate. Elytra a little longer than wide conjointly, sides feebly 

 arcuate, convex, a little more coarsely punctured than the thorax. Pro- 

 sternum densely and coarsely punctured, body more finely and less densely, 

 abdomen moderately coarsely not densely punctured. Length .08 — .10 inch ; 

 2 — 2.5 mm. 



The sexual peculiarities have already been remarked upon in the 

 generalities above. 



Occurs everywhere in the United States east of the Rocky Mts. 



C. pennatus Murr. — Oval, moderately robust, pieeo-testaceous, moder- 

 ately shining, sparsely pubescent. Head moderately densely punctate, front 

 feebly bi-impressed. Thorax nearly twice as wide as long, apex feebly emar- 

 ginate, base slightly arcuate, sides moderately arcuate, margin narrowly 

 reflexed, posteriorly slightly sinuate 9 oi" regularly arcuate %, disc con- 

 vex, moderately densely punctate. Scutellum coarsely but sparsely punc- 

 tate. Elytra longer than wide conjointly, apices rotundato-truncate, surface 

 moderately coarsely not densely punctate. Abdomen above very sparsely 

 punctulate. Body beneath sparsely punctate. Length .09 inch; 2.25 mm. 

 (PI. Ill, fig. 6). 



The males have an additional segment very plainly visible but 



