Ti^^^isrs.A.OTionsrs 



OF THE 



AMERICAN ENTOMOLOGICAL SOCIETY. 



VOLUME V- 



Revision of the S]»ecies of TROX of the United States. 



BY GEO. H. HORN, M. D. 



In the nintli and tenth parts of the Coleopterologische Hefte (Mu- 

 nich, 1872), Harold has published an elaborate monograph of the 

 species of Trox, in which ninety-three species are fully described from 

 the entire globe, fifteen remain unknown to him, of which seven be- 

 long to our fauna. With the view of endeavoring to supply the 

 deficiency, as far as our species are concerned, as well as of making 

 known to American students the results of Harold's studies, the fol- 

 lowing brief memoir has been prepared. 



Our species may be separated into two groups, characterized as 

 follows : 

 Scutellum hastate, that is, narrowed strongly near the base, the sides 



at middle angulate; sides of thorax never setose Group I. 



Scutellum oval, never hastate ; sides of thorax in many species setose...GRoup II. 



Group T. 



The first group contains all the larger forms and may be divided 

 into whyjed and apterous species. The latter have the elytra of oval 

 form, the humeri broadly rounded and no humeral umboue; the meta- 

 sternum is always very short and the rhomboidal space at its middle 

 much broader than long. The winged species have oblong elytra, the 

 humeri more abrupt aud the umbone always distinct; the meso- 

 sternum is normal in form and the rhomboidal space at middle at 

 least as long as wide. 



The following table gives the other characters : ' 



Elytra oval, body apterous, no humeral umbone scntellaris. 



Elytra oblong, body winged, humeral umbone distinct 1. 



1. Elytra with rows of tubercles very distinct and tomentose 3. 



Elytra with rows of tubercles much less distinct, never tomentose 3* 



TRANS. AMER. ENT, SOC. (1) JNAUARY, 1874. 



