82 PROCEEDINGS OF THE ACADEMY OF [1896. 



The small ■■species of the Pedis and Cladothrix. 



41. Perdita cladothricis n. sp. 



9 . — Length 3i-3S mm. Head and thorax shining, very dark 

 peneous, face entirely dark, clypeus and metathorax black. Abdo- 

 men dark sepia-brown, with a transversely elongate mark or band 

 of white at base of second segment. Legs dark brown, the anterior 

 knees and the tarsi, pale or whitish. Antennae dark brown. Vertex 

 very minutely sculptured. The usual pale hairs are very little de- 

 veloped anywhere, except at sides of end of abdomen ; the post- 

 scutellum and the sides of the metathorax are bare and shining. 

 Wings hyaline, beautifully iridescent, nervures fuscous, stigma pale 

 brown, 3d discoidal cell distinct, marginal with the substigmatal 

 portion longer than the poststigmatal, 1st submarginal broad, 2d 

 submarginal small and triangular, narrowing to a j^oint at junction 

 with marginal. 



S. — Length 2j-3 mm. Cheeks unarmed. IDiffers from the female 

 at once by the foce, which (with the mandibles except their reddish 

 tips) is entirely ivory-wliite below level of antennse, the white more- 

 over extending a short distance above the antennse, in the form of a 

 narrow line between them, and a broad prolongation on each side 

 between the antennse and the orbits, not quite as long as the scape, 

 and ending in an abrupt truncation. The antennse are mainly white 

 beneath. The tubercles, and the border of prothorax adjacent and 

 in front, and a portion of the anterior part of the pleura, are white. 

 The coxse, a considerable portion of the anterior and middle femora, 

 and part of the anterior tarsi, are white. 



The abdomen, in addition to the white band of the 9 , usually 

 shows a longer and narrower white band at base of 3d segment. 

 Venter dirty whitish, becoming brown at base and apex. 



Hab. — Las Cruces, N. M., very abundant on Cladothrix cryptan- 

 tha (det. E. O. Wooton), Sept. 15, 1895. On this occasion I took 6 

 ^,12 9 ; I do not think the males were really less numerous, but 

 owing to their small size and incessant activity they were less easily 

 caught than the females. The earliest date I have for this species 

 is a ^ taken on Cladothrix, associated with a new Oxyhelus, in the 

 beginning of September. Stray examples Avill be found at times on 

 other plants. On September 17th, four 9 were obtained by sweeping 

 from Pedis papposa, but Cladothrix was growing within a few feet 

 of the Pedis. On September 2od, a 9 Avas obtained from Bigelovia 



