Some time ago Prof. C. F. Baker sent me a lot of small bees collected by Dr. R. E. Kunzé at phoenix, Arizona, May 12, 1897, “on willows and various low herbs.” I have examined these with interest, as they belong to genera not recorded from that region; they prove to be as follows:

(1.) Perdita salicis, Ckll., 1896.–♂. ♀. Very many specimens.

(2.) Prosapis messilae, Ckll., 1896.–A few, mostly males.

(3.) Halictus meliloti, Ckll., 1895.–One ♀.

(4.) Halictus pseudotegularis, Ckll., 1896.–On April 12, 1897, I took at flowers of Sisymbrium, in Messila, N. M., a single Halictus which differed decidedly from Illinois H. tegularis, but, to my surprise, almost agreed with the Mexican H. pseudotegularis, except that the wings were clear. Now, among the Arizona bees I find examples of pseudotegularis with slightly dusky wings, as in the type, of that species; the second submarginal cell is noticeably smaller than in tegularis, and receives the recurrent nervure further from its end.