AMERICAN COLEOPTERA. 117 



Elytra not appendiculate in the males. 



Thorax finely punctured, sub-opaque, scarcely wider than long...Iaticeps. 



Thorax smooth, shining, distinctly wider than long lsevicollis. 



Elytra appendiculate in males. 



Thorax not longer than wide, its hind angles only yellow moerens. 



Thorax longer than wide, sides broadly rufous longicollis. 



Microlipus resembles Malachius in form and general aspect, but tbe 

 species are more slender and tbe legs longer. The antennae are 

 scarcely serrate and are inserted at the sides near the anterior margin 

 of front. The sexual characters serve also as a means of readily dis- 

 tinguishing Microlipus from all the other genera of the tribe in our 

 fauna. 



ASfTHOCOMUS, Erichs. 

 Anthocomus, Erichs. Entomog. i., 1840, p. 97. 



This genus may be distinguished from any in our fauna by its 

 eleven-jointed antennas inserted at the sides of the front, nearly or 

 quite at the anterior margin; tarsi simple and similar in both sexes; 

 elytra appendiculate in the males, not unlike those of the other sex in 

 form. 



There need be no difficulty in distinguishing the species of this 

 genus from those of the next, as in the latter the species are all small, 

 the epistoma much narrower between the insertion of the antennas and 

 the elytra of the males obliquely prolonged, tipped with yellow and 

 with a hook-like process above. 



A. Erichsonii, Lee. Proc. Acad. 1852, p. 165; otiosus % Er. Entom. p. 99; 

 lateralis, Lee. loc. cit. — Head black with tinge of green, shining, front impressed. 

 Antennse piceous, under side of four basal joints testaceous. Thorax broader 

 than long, sides broadly margined with yellow, median space black with tinge 

 of green, surface sparsely punctulate and with few greyish hairs. Elytra 

 parallel, black with bluish or fuliginous tinge, surface finely punctured and 

 rugulose and sparsely clothed with cinereous hairs. Under surface and femora 

 black, with slight greenish tinge, tibiae, tarsi and anterior coxae piceous. 

 Length .14 — .16 inch ; 3.5 — 4 mm. 

 Abundant in the Middle States. 



A. flavilabris, Say {Malachius), Journ. Acad. Ser. i., vol. v., p. 169; Lee. 

 (Anthoc.) Proc. Acad. 1852, p. 166; cceruleus Rand. (Malach.) Bost. Journ. ii., 

 p. 16. 



Resembles the preceding species in form and size, but the color is 

 more decidedly blue, and the thorax entirely unicolored and nearly 

 black. 



Females only are known. Occurs from the Middle to the Eastern 

 States. 



