16 Prof. T. D. A. Cockerell on 



east of Las Cruces, about 4000 feet, two at flowers of Senecio 

 Jilifolius, Sept. 10 (Townsend) ; Soledad Canon, Organ Mts., 

 one at flowers of Pedis papposa, Aug. 15 (Townsend). 



The abdomen, viewed from above, does not show the 

 black hair at the sides, which is so conspicuous in M. cleomis, 

 except on the last two segments. This separates it at a 

 glance from the typical female cleomis^ but cleomis var. lippice 

 has conspicuous lateral black hair only on the last two 

 segments, as in sidalcece. It would be easy to regard lippice 

 and sidalcece in the female as forms of one species, but the 

 males are quite different in the structure of their anterior 

 legs. There is a bare possibility that the female here assigned 

 to sidalcece does not belong to it, but is really a form of lippice, 

 in which case one of the next two species should probably be 

 mated with sidalcece ; but in the absence of absolute proof I 

 have followed the apparent probabilities. 



Megachile prosopidis } sp. n. 



? .—Length 12^-15-£ millim. 



Resembling M. sidalcece in the pubescence, but abdomen 

 subcylindrical and parallel- sided ; pubescence white, not 

 hiding the surface except in particular places ; the vertex and 

 roesothorax have some very scanty and short dark hair, 

 scarcely visible ; pubescence dense, forming conspicuous 

 white marks at sides of face, below tegulae, two white marks 

 on mesothorax in front converging posteriorly, a spot at 

 lateral hind angles of mesothorax and on hind margins of 

 abdominal segments, forming narrow entire bands ; pubes- 

 cence also dense on pleura and sides of mesothorax, but no 

 well-defined band at the scutello-mesothoracic suture ; band 

 on first abdominal segment produced at each side into a 

 triangular patch ; scopa white, black on last segment ; legs 

 black ; margins of tegulae dull ferruginous ; wings hyaline, 

 slightly smoky on margins ; antenna? black, flagellum 

 faintly ferruginous beneath ; mesothorax with large very close 

 punctures, not at all sparse on disk ; clypeu3 deeply and 

 broadly emarginate, the sides of the emargination directed 

 inwards, the middle occupied by a large lobe, so that the 

 opening, if closed by an imaginary line connecting the oppo- 

 site lower corners, would have a reniform outline ; labrum 

 with the apical lateral angles pointed, the apical middle 

 thickened but not produced, bearing a brush of brown hairs 

 directed somewhat backwards ; mandibles broad, 5-dentate 

 counting the inner angle, only the apical tooth large. 



