140 Mr. T. D. A. Cockerell on 
ii, Smaller, tegule black or piceous. 
Heriades prosopidis, sp. n. 
9. Long. 5 millim. 
Black, of the usual form; abdomen with narrow white 
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- 
tennee short, wholly dark ; eyes sage-green, except the anterior 
two-fifths, 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. Tegule 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 thorn- 
like prominence. Mandibles broad and tridentulate at apex. 
Hab. Mesilla, New Mexico, three at flowers of mesquite 
(Prosopis), in company with Prosopis mesille, P. asininus, 
and Perdita exclamans, May 7, 1896. 
I have also a single male, taken at Las Cruces, N. M., 
June 16, on Aster spinosus flowers ; it is like the female, but 
somewhat smaller, with a more densely pubescent face, longer 
antenne, and the tip of the abdomen exhibits four short teeth. 
This little species could be taken for ZH. vardolosa, Cresson, 
but the punctures of the third abdominal segment are no 
larger than those of the second. 
Heriades cactorum, sp. n. 
?. Length about 6 millim. 
Uniformly larger than H. prosopidis, but very similar to it. 
Lhe pubescence of the face forms two very conspicuous white 
bands at the sides and is fairly abundant about the antenne ; 
it does not at all conceal the surface of the clypeus. The 
punctuation of the pleura is somewhat closer than in proso- 
pidis, and the stigma is perhaps rather smaller, The flagellum 
becomes tinged perceptibly with dark brown. The eyes are 
