140 Mr. T. D. A. Cockerell on 



ii. Smaller, tegulae black or piceous. 

 Heriades prosopidis^ sp. n. 



? . Long. 5 millim. 



Black, of the usual form ; abdomen with narrow wliite 

 hair-bands. Head large, subquadrate; vertex shining, with 

 large extremely close punctures ; face somewhat hairy, sides 

 of face covered with white plumose hairs, forming very con- 

 spicuous patches ; clypeus punctured, more or less clothed 

 with silvery hairs ; mandibles dark, grooved without ; an- 

 tennae short, wholly dark ; eyes sage-green, except the anterior 

 two-iifths, which are intense black. Thorax shining, strongly 

 and closely but not confluently punctured ; pubescence scanty 

 over most of the surface, but forming patches in front of and 

 above wings and at sides of metathorax, the pleura also being 

 margined with white hairs. Tegulte shining piceous. Wings 

 iridescent, perfectly hyaline ; nervures and stigma black, 

 stigma quite small. Legs black, sparsely hairy, the four 

 hindmost tarsi clothed within with ferruginous hairs. Abdo- 

 men rather shiny, strongly and rather closely punctured, with 

 four conspicuous but very narrow white hair-bands. Apical 

 segment thinly clothed above with short silvery hairs. 

 Ventral scopa white. First ventral segment with a thoru- 

 like prominence. Mandibles broad and tridentulate at apex. 



Hab. Mesilla, New Mexico, three at flowers of mesquite 

 {Prosopis), in company with Prosopis mesillce, P. asininus, 

 and Perdita exclamans, May 7, 1896. 



I have also a single male, taken at Las Cruces, N. M., 

 June 16, on Aster sjnnosus flowers ; it is like the female, but 

 somewhat smaller, with a more densely pubescent face, longer 

 antenna, and the tip of the abdomen exiiibits four short teeth. 

 This little species could be taken for //. variolosa, Cresson, 

 but the punctures of the third abdominal segment are no 

 larger than those of the second. 



Heriades cactorum, sp. u. 



? . Length about 6 millim. 



Uniformly larger than H. ijrosopidis, but very similar to it. 

 The pubescence of the face forms two very conspicuous white 

 bands at the sides and is fairly abundant about the antennse ; 

 it does not at all conceal the surface of the clypeus. The 

 punctuation of the pleura is somewhat closer than in pj-oso- 

 pidis, and the stigma is perhaps rather smaller. The flagellum 

 becomes tinged perceptibly with dark brown. The eyes are 



