SUBGENUS TRICHAPION — KISSINGER 251 



Table 1. — Species groups of subgenus Trichapion Wagner — Continued 



rows of scales on the elj'^tral intervals, the beak of the male in dorsal 

 view rather evenly attenuate slightly distad of the antennal insertion 

 to the apical third, and the beak of the male noticeably pubescent in 

 the basal two-thirds. The other section related to A. patruele is 

 characterized by having a single row of generally inconspicuous 

 scales on the elytral intervals, the beak of the male in dorsal view 

 nearly parallel-sided in the apical half, and the beak of the male 

 nearly glabrous distad of the insertion of the antennae. The uniserial 

 or biserial pubescence is subject to some variation but the pattern 

 in general falls into one of the two groups. The dorsal pubescence 

 of the uniserial section is generally sparse and more inconspicuous 

 than that of the other section. 



The more notable intermediate forms are among the species whose 

 males have all three tibiae mucronate. Apion Jurtivum Fall and A. 

 confertum Smith have uniserially pubescent elytral intervals but the 

 beak is attenuate to the apical third. Apion commodum Fall has 

 biserially or triserially pubescent intervals and the beak is attenuate. 

 These three species were considered by Fall (1898) to be allies of A. 

 rostrum Say, a species with one row of inconspicuous scales on the 

 elytral intervals, beak attenuate to apical third, and the male with 

 two pairs of tibiae mucronate. The A. rostrum group may link the 

 A. patruele section to the A. simile section through the A. proclive 

 group, a member of which also has all thi'ee tibiae mucronate. 



The key to species is based entirely upon the male. Generally the 

 species of subgenus Trichapion are captured in a series and males are 

 usually present. In most cases it is possible to match males and 

 females of a species without too much difficulty by comparing the 

 sculpture and vestiture of the dorsal surface. 



The key is not based on the species groups as outlined in tables 

 2 and 3 because this would be too indefinite since these groups are based 

 on rather tenuous differences of degree rather than upon concrete 

 structural characters. The general plan of the key is as follows. 

 First the species with one or three pairs of mucronate tibiae are split 

 off. Then the A. griseum group with its modified front tibiae is 

 eliminated. The position of the antennal insertion is then utilized to 



