1896.] NATURAL SCIENCES OF PHILADELPHIA. 83 



wrlghtii. On September 25th, a few 9 were caught on Gutierrezia 

 sarothrce v. microcephala. 



42. Perdita pectidis n. sp. 



9 • — Head and thorax black, vertex greenish. Head of moderate 

 size, rounded, somewhat depressed on vertex. Sides of clypeus and 

 sides of face adjacent to orbital margin with sparse but large and 

 deep punctures. Vertex minutely rugulose, with sparse small punc- 

 tures. Cheeks less hairy than usual. Mandibles rufescent, whitish 

 at base, with dark tips. Clypeus with three rather large white 

 marks, the central one longitudinally oval. Sides of face with an 

 irregularly subtriangular white patch, narrowing to a point above, 

 about the upper level of the sockets of the antennae. Antennae with 

 the scape black, the flagellum sepia-brown. 



Mesothorax smooth, sparsely punctured, very shiny. Metathorax 

 blue-black. Collar, tubercles, and a couple of small spots on hind 

 border of prothorax, white. Tegulae hyaline subtestaceous. Femora 

 black, knees whitish. Tibiae and tarsi brown ; anterior tibiae in front, 

 and a stripe on middle tibiae pale yellow. 



Wings smoky, nervures and stigma sepia-brown. Poststigmatal 

 portion of marginal cell hardly as long as substigmatal ; 2d submar- 

 ginal narrowed more than half to marginal ; 3d discoidal distinct. 



Abdomen above very dark brown, segments 1-4 each with an 

 oblique white stripe on each side. Pygidial area dark subrufescent. 

 Venter dark brown. 



S. — Wings clear. Metathorax quite blue. Mandibles white with 

 rufescent tips. White markings of face as in cladothricis $ . Pale 

 marks of abdomen reduced, sometimes to 4 or 5 small spots, which 

 are then pale yellowish. 



Hab. — Las Cruces, N. M., in numbers on Pedis papposa, Sept. 17, 

 1895. It is closely allied to cladothricis, but differs at once by the 

 face of the 9 iiot being all dark, and the different abdominal mark- 

 ings. 



On September 20th, I took four 9 P. pectidis from flowers of Tri- 

 hulus maximus, and two, also 9 > from flowers of Wedelia incarnata. 



With the P. pectidis on Pedis papposa were a few P. fallax, 9 

 which I at first supposed to be a variety of it. P. fallax is, however, 

 distinguished by its greenish head and thorax (or at least the meso- 

 thorax more or less greenish), scape pale yellowish below or with a 

 yellow stripe, face-markings tinged distinctly yellowish, clypeus pale, 

 sometimes with two black bars, diverging below, and the usual black 



