58 PROCEEDINGS OF THE ACADEMY OF [1896. 



9. Perdita nevadensis n. sp. 



9 . — Length almost 6 mm. Head so dark green as to seem 

 black ; thorax pitch black, with the metathorax green. In certain 

 lights the prothorax and anterior part of the mesothorax present a 

 greenish lustre. Head moderately large, broader than long, de- 

 pressed on vertex ; clypeus shaped like a rather low cocked-hat, 

 flattened at the top, the teeth of anterior margin dark and rather 

 long. Vertex dull, rugulose. Face and cheeks with sparse incon- 

 spicuous hairs. Antennae dark brown ; the flagellum paler, inclin- 

 ing to yellow beneath. Face-markings pale dull yellowish ; clypeus 

 pale with two broad divergent black bars and a black dot distad of 

 each, supraclypeal mark represented by two round or suboval spots; 

 dog-ear marks represented by obscure small spots, not alike on both 

 sides ; lateral pale patches triangular, the upper angle an acute one 

 and level with the insertion of the antennae, the shortest side of the 

 triangle at least two-thirds the length of the longest. Mesothorax 

 shiny, hardly granular, sparsely hairy and punctate. Thorax all 

 dark, except the tubercles, which are pale yellow. Metathorax 

 granular. 



Tegulsepale testaceous. Wings hyaline, faintly smoky, uervures 

 and stigma pale brown, stigma centrally subhyaline. Marginal 

 cell moderately long, obliquely truncate, poststigmatal portion a 

 very little longer than substigmatal. Second submarginal large, 

 narrowed on its distal side one-half to marginal. Third discoidal 

 distinct. Legs dark brown, anterior knees, anterior tibiae in front 

 and stripe on middle tibiae, yellow. 



Abdomen rather broad, above and below piceous, segments 2-4 

 above with distinct oblique lateral yellow marks. The mark on the 

 2d segment is on one side broken into two. 



Hab. — Nevada, one specimen sent by Mr. Fox. 



The following tables will separate nevadensis from some species 

 which it superficially resembles. 



A. (1). Lateral marks efface triangular, terminating in a point, 



^=^nevadensis $ . 

 (2). Lateral marks of face truncate at end and notched within, 



=affi7iis 9 • 



B. (1). Face-markings whitish, lateral marks narrower, abdom- 



inal marks white, ..... =Jallax 9 . 



(2). Face-markings yellow, lateral marks broader, abdominal 



marks yellow, .... =^nevadensis 9 . 



