306 AMERICAN PACHYBRACHYS (cOLEOPTERa) 



Appendages. — The antennae are rarely entirely yellow or 

 entirely black; typically they are pale basally with the first two 

 joints more or less blackish on the upper side, and the outer four 

 to six joints more or less dusky or blackish. Legs yellow with the 

 tarsi dusky, tibiae with a dark apical or subapical cloud, the 

 femora with a median dark spot or ring. By reduction the legs 

 may become entirely pale, while by an extension of the dark 

 marks they become black with the extremities of the femora and 

 bases of the tibiae narrowl}^ pale — and more rarely entirely 

 black. 



Sexual characters. — In common with most Coleoptera the males 

 are, on the average, smaller and less robust than the females. 

 The abdomen in the male is flat or more or less concave in pro- 

 file, the last ventral fiat or broadly feebly impressed; in the 

 female the abdomen is convex beneath, the last segment with a 

 deep rounded fovea. With few exceptions the antennae are 

 obviously longer in the male; the basal joint is also often some- 

 what larger in this sex, but these organs are not otherwise modi- 

 fied sexually in our species.^ The terminal joint of the maxillary 

 palpi is in many species more widely truncate at apex in the male; 

 the front tibiae are modified at apex in two species, the front 

 tarsi are sometimes visibly broader, while the front claws are 

 slightly to c^uite strongly enlarged in numerous species in this 

 sex. In the female the terminal joint of the maxillary palpi is 

 pointed with the tip narrowly truncate as a rule, and the front 

 claws are usually just visibly larger than those of the four posterior 

 feet. The hind thighs are in general more elongate in the males 

 according to Jacob^y, but I am inclined to believe this is more 

 apparent than real, the thighs seeming to be shorter in the female 

 because of the greater length of the ventral surface in this sex. 

 As a result, they attain the last segment in the female, while they 

 reach the abdominal apex in the male. There is obvious a 

 general tendency to a broader, more suffused maculation in the 

 female, as well as a denser more confused punctuation. 



The tabulation of the grcuit number of species involved in this 

 revision, even in the imperfect way in which it has been accom- 

 plished, has proven a very difficult task. Just as was found to l)e 



'The tcniiinal joint is somewliat dilated in the male of laticolUs. 



