28 THE CANADIAN ENTOMOLOGIST 



The reference to Trimicra is somewhat provisional, although 

 probably correct. 



Genus Rhabdomastix Skuse. 



Subgenus Sacandaga Alexander. 



Rhabdomastix flava colcradensis, subsp. n. 

 Allied to R. flava flava; antennal flagellum black; pleura? 

 white-pruinose; femora and tibiae tipped with brownish; wings 

 with Ri almost perpendicular to i?2+3; Rz almost straight; m 

 very long. 



Male. — Length 5.5 mm.; wing 6.9 mm. 



Rostrum and palpi brown. Antennae with the first scapal 

 segment yellowish, the remainder of the organ black. Head 

 pinkish gray with a very narrow and indistinct median line of 

 darker. 



Pronotum yellowish, a little browner medially, the sides of the 

 scutellum whitish. Mesonotal pra?scutum dull whitish yellow, 

 dusted sparsely with a grayish pollen, and with three broad, reddish- 

 brow^n stripes; the broad, middle stripe ends far before the trans- 

 verse suture and is slightly bifid caudally; scutum with the median 

 area whitish, the outer lateral portions of the lobes dark brown; 

 scutellum bright yellow; postnotum reddish brown, sparsely prui- 

 nose. Pleura yellow, more bluish white pruinose on the meso- 

 pleurites. Halteres light yellow. Legs with the coxae brownish; 

 trochanters dull yellow; femora light brown, broadly tipped with 

 dark brown; tibiae brown, very narrowly tipped with darker; tarsi 

 brown. Wings opalescent, subhyaline; costal region a little more 

 yellowish; stigma ill-defined, yellowish brown, veins dark brown. 

 Venation :. i?2 short, almost perpendicular to i?2+3 at the fork; 

 cress-vein m very long so that the outer deflection of Mz is greatly 

 reduced, almost punctiform. 



Abdominal tergites brownish yellow; sternites a little brighter. 



Habitat. — Colorado. 



Holotype, d^,* Platte Canyon. Colorado, July 17, 1915 (Oslar). 



Close to typical flava Alexajider of Northeastern America, 

 but sufificiently distinguished by the black antennal flagellum, the 

 mesopleura more whitish pruinose, the femora and tibia' tipped 

 with brown and in the slightly different venational details. 



