196 DIPTEEA. 



tinge ; hyaline on the antero-proximal half only ; the grey shadow in the first submarginal cell rather 

 narrow. 

 Length, tf , 22-26 millim. ; $ , with the ovipositor, 23-30 millim. 



Hob. United States, Arizona (ComstocJc 1 ). — Mexico, Northern Sonora (Morrison). 



Seventeen males, and as many females, from Northern Sonora. 



I have seen Dr. Williston's types. 



The colouring of the thoracic dorsum is variable, the grey prevailing over the brown, 

 or vice versd; the legs in some specimens are more suffused with red than in others. I 

 have thought it useful to give a fresh description of the species. 



7. Promachus notolis, sp. n., <j $ . 



Face yellow pollinose, with a rather dense, yellowish, shining tuft of hair on the facial tubercle (less dense and 

 more bristly in the female ; in one of the female specimens some of the bristles are black) ; similar tufts 

 of hair on the cheeks ; palpi beset with black bristles ; occiput brownish-yeUow pollinose, with yellowish 

 and brownish hairs and bristles ; antennas black. Thorax : dorsum dark brownish-black, opaque ; dorso- 

 central stripes brownish pollinose in an oblique light, the middle line nearly obsolete ; the sides of the 

 dorsum, humeri, and pleuree yellowish-brown poUinose ; macrochsetse black ; brownish-yellow, long, soft 

 hairs on the pleura? and on the scutellum. Abdomen black, opaque above; lateral and posterior margins 

 of segments 2-7 (2-5 in the female) brownish-yellow pollinose (the posterior margins occupy about one- 

 quarter of the breadth of the segments in the male, and still less in the female, the lateral margins are 

 broader) ; the tbree basal segments clothed with fulvous hair (the yellowish hairs on the paler portions of 

 the other segments can be discerned under the magnifying-glass only); venter brownish-yellow pollinose. 

 Male forceps comparatively small, elongate, with sparse, black hair. Legs dark rufous, blackish about the 

 knees, beset with pale yellowish, inconspicuous hairs, the bristles black ; tarsi black ; pulvilli brownish (and 

 not yellowish-rufous as usual) ; front coxa? beset with whitish hair. Wings with a pronounced brownish- 

 yellow tinge ; the grey shadow in the first submarginal cell large, occupying the whole disc of the cell ; a 

 vestige of a shadow in the marginal cell. 



Length, 3 , 26 millim. ; $ , 30-32 millim. 



Hab. Costa Rica, Cache (Bogers). 



One male and two females. 



An undescribed species from Texas, of which I have several male and female spe- 

 cimens, in its colouring very much resembles P. noUlis ; the principal differences are 

 that the grey cross-bands on the hind margins of the abdominal segments occupy nearly 

 one half the breadth of the segment ; that the grey shadow in the first submarginal 

 cell is much smaller and narrower (it occupies about one third of the breadth of the 

 cell) ; and that the pulvilli are yellowish-red and not brown. 



The other species of Promachus from our region (mentioned in the table, ante, 

 p. 192), all of which are from Mexico, described by previous writers, are as follows : — 



Promachus magnus, Bellardi, Saggio &c. ii. p. 26. 



