[25] NORTH AMERICAN COLEOPTERA. 181 



amongst those having occipital fovea?, the only ones exhib- 

 iting sexual modification of the dorsal surface of the abdo- 

 men; while those which have two large spongiose lateral 

 foveas and a minute nude median puncture are the only 

 ones which possess a sexual modification of the middle 

 joints of the antenna?, although there are many species which 

 have the antenna? similar, as there are several in the pre- 

 ceding section which have the abdomen similar, in the two 

 sexes. 



Again, those having three nude pronotal fovea? which are 

 unequal, are distinguished by a complete absence of occip- 

 ital fovea?, and, considering the sexual modifications appar- 

 ent in other portions of the group accompanying such 

 decided differences in the fovea?, we might be led to expect 

 a peculiarity here also. 



From Galveston, Texas, I have before me two species of 

 this section. One of these is represented by seven males 

 and three females, the other by three males only, the latter 

 having an almost impunctate head and longer elytral striae; 

 these have the first segment elongate, and the middle por- 

 tion of the dorsal surface behind its apex exhibits sexual 

 modifications consisting of excavations and minute tubercu- 

 lations of the greatest complexity. The males of the first 

 species have shorter elytral stria?, a more punctate head, 

 and also exhibit sexual characteristics affecting the dorsal 

 surface of the abdomen, although of an entirely different 

 kind. The first two segments are perfectly normal, the first 

 slightly elongate, but the third is very broadly and feebly 

 impressed, the impression having in the middle a tuft of 

 long erect sparsely-placed seta?. The sexual characters, 

 therefore, affect the same part of the body as in Bryaxis, but 

 instead of being limited mainly to the first segment, it is 

 the portion posterior to this which is principally modified. 

 These species are, however, well distinguished from Bryaxis 

 by the presence of lateral carina? on the lower surface of 

 the head. . 



