H. C. FALL. 185 



B. exiguus Horn. 



Specimens before me from Florida, Ohio, Missouri, Ari- 

 zona and California do not appear to be separable, and indi- 

 cate this to be a variable and widely dispersed species. Ac- 

 cording to description, the types have the head and thorax 

 black and the sides of the elytra narrowly so, but the color 

 may become almost entirely rufous, in which case a small 

 spot on the head, the tip of the humeral callus and the nar- 

 row sutural interspace usually remain blackish. In the Ari- 

 zona and California specimeus the spur of the hind tibiae is 

 noticeably though not greatly longer than in eastern ex- 

 amples, but no other difference of moment has been noticed. 

 The species was described from two Kansas specimens, but 

 on attempting to compare with these some years ago I found 

 none such in the Horn collection ; in fact there were no speci- 

 mens on the label, but beside it were several Arizona ones 

 which were perhaps placed there tentatively. The number of 

 denticles on the hind femur may be either two or three, and 

 these vary much in development. As indicated previously, 

 it is very doubtful if floridce is distinct from exiguus, all of 

 whose essential characters are those of the preceding group. 

 B. musculus Say. 



One of the most distinct species in our fauna, and most of 

 its pecularities have apparently escaped record. Say de- 

 scribes the antennas as yellow at base and tip, and piceous in 

 the middle. Horn says they are usually colored thus, but 

 are often entirely pale. Judging from the material before 

 me this difference is purely a sexual one, the males having 

 entirely yellow, and the females bicolored antennae. The 

 eyes are unusually deeply emarginate, the tip of the ab- 

 domen is deflexed in the male, the hind thighs are minutely 

 serrulate at the middle beneath (observed elsewhere only in 

 subserripes) , and the hind tibiae are finely granulato-serrate 

 posteriorly throughout their length. The contrast between 

 the bright, yellow hind tarsus and the black tibia and femur 

 is striking and unusual. The three denticles of the hind 

 femur are more distant than usual from the anterior tooth, 

 and between them may be seen in some specimens a fourth 

 very small denticle. 



TRANS. AM. ENT. SOC, XXXVI. (24) JULY, 1910. 



