J. R. MALLOCH 287 



5. Frons when seen from above with the ocellar triangle rarrietl forward in 

 the form of an opaque black wedge to, or almost to, anterior margin, 

 dividing the silver}' white portion into two separate areas. 



dorsalis Loew 

 Frons when seen from above with the anterior half entirclj- silver}- white, 

 the anterior wedge-like extension of ocellar triangle never distinct, and 

 rarely darker than surrounding areas. 



dorsalis var. partita var. n. 



Schoenomyza convexifrons sp. n. 



Male. — Black, opaque, covered with dense olive-gray pruinescence. Head 

 black, gray pruinose on occiput, covered with dense golden pruinescence on 

 frons, face and cheeks, when viewed from in front the ocellar triangle, and upj)er 

 half of each orbit appear black-brown; antennae black, with inconspicuous 

 whitish pruinescence, most distinct at apex of second joint; proboscis black, 

 palpi fuscous. Thoracic dorsum with four brown vittae, two between the 

 rows of dorso-centrals, and one on each side between the dorso-centrals and 

 intra-alars; in front of scutellum on mesonotum there is a short brown streak 

 between the median pair of vittae, and on disc of scutellum there is a brown 

 mark. Abdomen with a pair of large, poorly defined brownish black spots 

 on disc of all dorsal segments. Legs black. Wings clear, veins black, cross- 

 veins hardly more conspicuous than th(> other veins. Calyptra and halteres 

 whitish. 



Frons in profile slightly convex, at vertex a httle over half the width of 

 head, narrowed anteriorly, its central length about equal to its greatest width; 

 ocellar bristles long and strong; each orbit with three bristles, the upper one 

 strongest, in addition to the bristles there arc numerous short hairs on orbits; 

 antennae below the average size for the genus, third joint about twice as long 

 as wide, sharply angulated at apex on upper side, arista tapered, almost nude; 

 face in profile slightly receding, parafacials narrow; cheek as high as width of 

 third antennal joint; one short bristle above the strong vibrissa. Acrostichals 

 weak, arranged in pairs from anterior to jiosterior margin of disc, usualh' six 

 pairs present (two+four). Chaetotaxy of legs as in chrysostoma Loew. Wings 

 narrow; last section of fourth vein at least twice as long as preceding section, 

 penultimate section of costa longer than i)enultimate section of fi)urth vein; 

 outer cross-vein at more than its own length from apex of fifth. 



Female. — Differs in color from the male in having the frons, face, and 

 cheeks pale olive-gray prtiinosc, and the cross-veins of the wings noticeably 

 infuscatcd. Length, wafe, 3 mm., female, 4 mm. 



The frons is broader than in the male and slightly less buccate. 

 In other respects the sexes agree very closely. 



Type.— d"; Milbrae, California, March 20, 1908. [A. X. S. 

 No. 6204]. Paratypes. — 4 cT, 2 9, topotypical. 



TRANS. AM. EXT. SOC, XLIV. 



