274 PROCEEDINGS OF THE NATIONAL MUSEUM vol. no 



than those of the female, except in A. meorrhynchum Philippi. The 

 four species apparently do not overlap in range. It is possible that 

 A. modestum Smith overlaps A. simile in Nebraska or Iowa. A. pro- 

 pinquicorne Fall is more southern in distribution, occurring in southern 

 Texas and Mexico. A. meorrhynchum Philippi occurs in Chile. 



A. simile differs from A. modestum and A. propinquicorne by the 

 longer beak of both sexes and more distally inserted antennae. The 

 latter two species are closely allied — small, densely pubescent, with 

 antennae inserted near the base of the beak. The male of A. propin- 

 quicorne has a beak which is slightly longer than the pro thorax; the 

 antennae in both sexes are inserted close to the base of the beak at a 

 distance from the eye less than the width of the frons; and the elytral 

 intervals are biserially pubescent. The male of A. modestum has a 

 beak which is as long as the pro thorax; antennae of male are inserted 

 at distance from eye equal to width of frons; and the elytral intervals 

 are generally uniseriaUy pubescent, but the scales may be confused, 

 appearing in part as two rows. A. meorrhynchum is well distinguished 

 by the antennae which are inserted at about the middle of the beak, 

 the antennal scape is longer than the next five segments, and the 

 elytral intervals are clothed with four to six rov\'S of scales. 



Two lines of species groups seem to be related to the holarctic species, 

 Apion simile. One line is composed of the A. proclive and A. glyphi- 

 cum groups. They have been differentiated from A. simile along the 

 folloAving lines: the male mucrones are generally strongly dentate, 

 the frons is narrow, in some cases narrower than the dorsal tip of the 

 beak, head is much more strongly constricted dorsally behind the eyes, 

 and the female beak, while elongate, is not cylindrical but gradually 

 attenuate toward the apical region and the apex is generally expanded 

 laterally. The A. proclive group overlaps the range of the A. simile 

 group in the western portion of the United States and extends well 

 into Mexico. The A. glyphicum group overlaps the range of the A. 

 proclive group in Mexico and extends into Central America. 



The other line is composed of the A. griseum, A. spinitarse, A. 

 punctulirostre, and A. submetallicum groups. They have become 

 differentiated from A. simile along the following lines: the A. griseum 

 group exhibits additional male secondary sexual modifications of the 

 fore tibiae; in both sexes the beak is more attenuate toward the apical 

 third; generally the female beak is expanded laterally at the tip; 

 the frons is comparatively broader, and in general the antennae of the 

 male are inserted closer to the eyes at a distance less than the width 

 of the frons; the males of the A. spinitarse and A. punctulirostre groups 

 have only the middle tibiae mucronate; the A. submetallicum group 

 exhibits modification of the beak in that it is more attenuate to the 



