AMERICAN COLEOPTERA. 113 



Notes on some little known Genera and Species of 

 COLEOPTERA. 



BY GEORGE H. HORN, M. D. 



The following pages contain the results of fragmentary studies made 

 at various times, with notes on some genera sufficiently well known by 

 name of which the descriptions have been necessarily imperfect. 



Several new genera are described here for the first time, one being 

 a contribution from Dr. LeConte in order that the description might 

 accompany the figure. Species are described in several genera now for 

 the first time known in our fauna as Da sy cents and Oniticellus. 



Considerable space has been devoted to Polymoechus and many details 

 given on the plate, the better to elucidate its systematic position, it being 

 now accepted as a Rutelide rather than a Dynastide. 



A few genera have been figured in order that the student might be 

 able to acquire a better idea of their external form than that obtained 

 from description alone. 



One foreign genus has been studied and its affinities pointed out. Myrme- 

 cospectra seems not to have fallen under the observation of any careful 

 student since the days of Motschulsky, and the position assigned it by that 

 author as well as that given in the Catalogus are equally erroneous. 



The species formerly placed in Lichnanth? and Dasydera have been 

 synoptically treated and placed under Amphii omu , the two genera above 

 mentioned not presenting characters sufficient for their separation. 



L.EPTINUS Mull. 



Having had occasion to examine our species of this genus with the 

 view of describing the parts of the mouth, several important differences 

 between the two species have been observed which are of sufficient moment 

 to require the creation of a new generic name for our larger form. 



These characters in brief are as follows : 



Head entirely without eyes; presternum not separating the anterior coxse. 



Leptinus. 



Head with translucent eye spots at the hind angles of the head; presternum 



separating the coxse Lep till ill us. 



The latter genus based on L. validus Horn, being much larger than 

 the other was used in preference for dissection, and the sketches on the 

 accompanying plate were made from it. 



The head viewed from above presents a well marked hemihexagonal 

 frontal suture. The labrum is transverse, connate with the front, the 

 suture well marked and nearly straight. 



TKANS. AMER. E.NT. SOC. X. (29) Al'GlST, 1882. 



