10 CALIFORNIA ACADEMY' OF SCIENCES. 



tips, labrum, clypeus, a spot beneath the insertion of each 

 antennae, and the antenna? beneath, yellow ; the latter 

 above testaceous; dorsulum and scutellum glabrous, 

 seemingly impunctate; metathorax at extreme base trans- 

 versely roughened ; tegulae and greater part of four an- 

 terior legs yellow, the hind legs testaceous ; wings hyaline, 

 iridescent, the nervures and stigma fuscous-white; ab- 

 domen testaceous, with an irregular band on segments 

 2-5, which is emarginate posteriorly; ventrally the ab- 

 domen is entirely yellow, in some specimens stained with 

 testaceous at base and apex ; the apical segments are 

 sparsely clothed with pale pubescence. Length, 4 mm. 



Three specimens. Margarita Island, L. Cal. {//(lines). 

 March. The entirely yellow ventral segments of the ab- 

 domen will distinguish this species. 



Perdita arcuata n. sp. 



$ . — Head and thorax dark metallic green, sparsely 

 clothed with pale pubescence; clypeus with rather fine, 

 not very close punctures, its anterior margin strongly and 

 widely arcuated ; antenna? separated by a rather strong 

 ridge, which extends from base of clypeus almost to 

 anterior ocellus; front and vertex with exceedingly fine 

 and close punctures; cheeks rather sparsely punctured, 

 not dentate beneath; antennae dark fuscous, dorsulum 

 and scutellum very finely and closely punctured; tegulee 

 testaceous ; wings hyaline, iridescent, nervures and stigma 

 testaceous ; the second submarginal cell is almost triangu- 

 lar, being greatly narrowed above ; legs brownish with 

 white pile, the fore femora at tips and tibicE in front, 

 yellow; abdomen black, the apical margins of the seg- 

 ments broadly rufo-testaceous ; the mandibles, except 

 tips, and the labrum are yellow. Length, 4 mm. 



Two specimens. Calmalli Mines, L. Cal. {//aiiies). 

 April. This species belongs to Smith's genus, Macrotera, 

 which Cresson regards as a synonym of Perdita. 



