276 COLEOPTERA OF NORTH AMERICA. 



Elytra shorter than the ahdomen ; 

 Oral organs perfect ; 



Middle coxae contiguous. Rhipiphorini. 



Middle coxse widely separated. Myoditini. 



Oral organs atrophied. Rhipidiini. 



Tribe I.— EVANIOCERItfl. 



In this tribe, represented in our fauna only by Pelecotoma fla- 

 vipes Mels., from the Atlantic States, the oral oi'gans are perfect; 

 the eyes are emarginate, not very finely granulated, and the an- 

 tennaa are inserted before them at the sides of the front ; the 

 scutellum is not covered by the base of the prothorax ; the elytra 

 are as long as the abdomen, and are contiguous along the suture ; 

 the middle coxa? are very slightly separated by the narrow meso- 

 sternum ; the epimera of the metathorax are small, and the epi- 

 sterna are narrow. There are five ventral segments. 



The genera belonging to this tribe resemble in form Mordel- 

 lidae, and in one foreign genus (Ctenidia) the lateral margin of 

 the thorax is well defined ; it can be distinctly traced in our spe- 

 cies. It is very doubtful whether this tribe should be retained as 

 a member of the present family, but nothing is yet known of the 

 habits of the larvae. 



The genus Pelecotoma is distinguished from foreign genera by 

 the tarsal claws being feebly bidentate, and the vertex not ele- 

 vated. 



Tribe II.— RHIPIPHORINI. 



Oral organs perfect ; eyes entire, very finely granulated ; an- 

 tennae inserted between the eyes upon the front, biflabellate in the 

 males, serrate in the females ; scutellum covered by a lobe of the 

 base of the prothorax ; lateral suture of prothorax entirely want- 

 ing ; elytra not much shorter than the abdomen, pointed behind, 

 not meeting closely along the suture ; middle coxae slightly sepa- 

 rated ; epimera of metathorax large, episterna wide ; ventral 

 segments five ; tarsi long ; claws bifid at tip. 



Cuneiform insects with coarsely punctured and sparsely pubes- 

 cent surface, of varied colors, found upon flowers. 



Our species all belong to two genera, both having the vertex 

 very much elevated : — 



Labrum long, triangular, maxillse prolonged. Macrosiagon. 



Labrnm short, maxillse not prolonged. Emmenadia. 



No species has yet occurred in the Pacific district. 



