40 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



Museum: one female, Phoenix, Arizona (A. K. Fisher), in the collec- 

 tion of J. R. Malloch: and one female, Holly Springs, Mississippi 

 (H. W. A.), in my collection. The specimen from Owen's Lake has 

 an arista with a rather long penultimate joint but agrees in other 

 respects with the typical, and is probably the same species. 



Genus OESTROHILARELLA Townsend 



Oeslrohilarella Townsend, Insecut. Insc. Menst., vol. G, p. 162, 1918. 

 Genotype, Hilarella aristalis Coquillett from southern Illinois. 



Readily distinguishable from Hilarella, Phrosinella, and Eumacrony- 

 chia by the absence of any definite angle between the facial and buccal 

 margin, when viewed from the side, and the presence of a globose or 

 subglobose abdomen upon which the macrochaetae are scarcely 

 differentiated. The genus also differs from Hilarella in having the 

 last section of the fifth vein much less than half as long as the preced- 

 ing section, and in the absence of a costal spine; from Phrosinella 

 in having the lunule minute and largely concealed, the frontal rows 

 not extending beyond the base of the antennae and not suddenly 

 divergent below, the parafacials not suddenly constricted near the 

 lower inner corner of the eye; from Eumacr onychia in not having the 

 pollen of the abdominal segments limited to dense, even, basal bands. 

 Other distinguishing characters are as follows; a single frontal row 

 on either side of the vitta; orbital bristles present in both sexes; 

 antennae extending much more than half the distance to the vibrissae, 

 which are inserted just above the oral margin; proboscis much 

 shorter than head height; small bristly hairs on less than the lowest 

 half of the facial ridges; in profile, head length at vibrissae much less 

 than at base of antennae; no pale hairs on bucca or back of head 

 about the oral cavity; two sternopleural bristles present; wings 

 with but a few bristles at base of third vein. 



A single North American species is referable to this genus, 



OESTROHILARELLA ARISTAUS (Coquillett) 



Hilarella aristalis Coquillett, U. S. Bur. Ent., Tech. Ser., no. 7, p. 129, 

 1897. 



The front of the male is disticntly wider than that of the female 

 (measurements of the ratio of the front at narrowest to head width, 

 for males an average of 0.365 for two measuring 0.36 and 0.37, 

 respectively; for females an average of 0.308 for six measuring 

 0.29, 0.29, 0.30, 0.31, 0.33, and 0.33, respectively); one reclinate and 

 two proclinate orbital bristles; frontal vitta black and at level of 

 lowest orbital slightly wider than either parafrontal; third antennal 

 joint black, three times as long as the second; arista thickened on 

 basal three-fourths; parafacials bare on lower half. Thorax gray 

 pollinose with four distinct black vittae; three postsutural dorsocen- 



