NORTH AMERICAN COLEOPTERA. 33 



A study or some genera of El,ATERIDJR. 



BY GEORGE H. HORN, M. D. 



While preparing the portion of Dr. LeConte's paper for publication 

 relating to Elateridae, my attention was drawn to the confusion existing 

 in several genera from the scattered descriptions of the species, and the 

 absence, in many cases, of comparisons between them. To supply the 

 want which appeared to exist I have made the following studies : 



Of the species described in the following pages my cabinet contains 

 specimens carefully compared with the types described by Dr. LeConte, 

 the new species being also in my cabinet. Notwithstanding the fact that 

 many of them have been several times more or less fully described I 

 have thought it well to repeat the descriptions in order that they might 

 be better compared and so enable future discoveries to be more readily 

 correlated with them. 



HOKISTOSfOTlTS Cand. 



This genus contains those species for a time enrolled in Cardiophorus 

 in which the margin of the thorax is moderately well defined in the basal 

 half, the edge being at the same time coincident with the suture which 

 divides the dorsal from the pectoral region of the prothorax. 



In the lists which have been published eight species are recorded as 

 occurring in our fauna, in the following pages six new ones will be found 

 described and one {exoletus) added which has been known only from 

 South America. 



The occurrence of species with simple claws in our fauna is here indi- 

 cated for the first time, and three are recorded with the claws cleft at tip. 

 All our species have the free angle of the coxal plate rounded. Some 

 have the humeri so broadly rounded as to lead to the suspicion that they 

 are apterous. One species (puUatns) is certainly apterous, and I have 

 very little doubt that the same will be found of those with broadly 

 rounded humeri as {nanus, basalts, transfugiis, definitus and sufflatus. 

 From this fact some modification of the table of genera as given by 

 Candeze (Elat. iii, p. 104) is required, and Coptostethus must be placed 

 next to Cardiophorus, from which it should be directly distinguished. 



TRANS. AMER. EXT. SOC. XII. (9) DECEMBER, 1884. 



