AMERICAN COLEOPTERA. 289 



In all attempts at an arrangement of the species of Epuraea which 

 have been hitherto made, the extent of separation of the hind coxae 

 has been taken as a starting point, and this has been so magnified in 

 importance that Reitter and Crotch have proposed to separate those 

 species with distant coxae under generic or subgeneric names. I am 

 satisfied that any arrangement on this basis will produce anything but 

 a natural sequence of species. 



The sexual characters of the males seem to afford the means for a 

 very natural grouping and as that sex have one peculiarity in common, 

 the additional segment and special characters peculiar to series only, 

 we have in the first instance the means of determining the males 

 with unerring certainty and the group to which they should be 

 referred almost as positively. 



These groups may be defined as follows : 



Middle tibiae dissimilar in the two sexes, that of the male sinuate within and 



thickened at tip, that of the female slender. (PI. Ill, fig. 19) Group I. 



Middle tibite similar in the two sexes, slender. 



Posterior tibiae of both sexes similar and slender Group II. 



Posterior tibiae of the male slightly arcuate, slender at basal half, suddenly 



broader at apical half. (PL III, fig. 20) Group III. 



These are the only groups known in our fauna, others occur in 

 Europe with the femora dentate beneath or the posterior tibiae 

 toothed at middle, in the male. 



GrROUP I. 

 This group contains by far the larger number of the species in 

 our fauna as well those of the greatest size. The middle tibiae of 

 the male are sinuate on the inner margin the apex being prolonged 

 inward to a greater or less extent, the outer apical angle being 

 obliquely truncate. This set of characters varies in the degree of 

 development so that in rufida the middle tibia becomes deformed in 

 aspect, while in fulvescens the sinuation is barely perceptible and the 

 tibia seems to be merely stouter than that of the female. 

 The species arrange themselves in the following manner: 



A. — Intercoxal process of abdomen broad, truncate. 



Sides of thorax moderately arcuate, gradually broader to base. 

 Form oblong, color piceous, elytra conjointly not as wide as long. 



isionogania. 

 Form broadly oval, color yellow, elytra conjointly as wide as long. 



Hornii. 

 Sides of thorax strongly arcuate, at base narrowed or sinuate, hind angles 

 acute, slightly prominent. 



Form broadly oval, elytra narrower at apex helvola. 



Form more oblong, elytra scarcely narrowed to tip rufa. 



TRANS. AMER. ENT. SOC. VII. (37) JULY, 1879. 



