290 Journal New York Entomological Society. [Voi. xxi. 



DIASTATA Meigen. 



Hind cross-vein enclosed in a brown mark 2. 



Wings hyaline, slightly infumated along the costal portion, the costal cell 

 mostly black, the hind cross-vein slightly nearer the end of the fourth 

 vein than the anterior cross-vein. 2.5 mm. (Wash.*) .inodesta n. sp. 



2. Costa and posterior cross-vein infumated ; arista two times as long as the 



third antennal joint 3- 



Brown markings of wing including the anterior cross-vein, the costa paler 

 than the markings ; arista shorter 4. 



3. Posterior cross-vein considerably nearer the anterior cross-vein than the 



end of the fourth vein; thorax with four indistinct vittae. 2.5 mm. 



(Martin's Falls, Canada.) tenuipes Walker. 



Posterior cross-vein nearer the end of the fourth vein than to the anterior 

 cross-vein ; mesonotum not vittate ; middle coxae of male with very 

 long hairs. 4 mm. (Eur.; Asia; N. H., Wash.*) ... .vagans Loew. 



4. Wings brown, marked with three fasciae, the first subbasal, the second be- 



tween the cross-veins, starting at the second vein and interrupted or 

 not by the discal cell, the third subapical and more or less inter- 

 rupted at the fourth vein ; base of abdomen with pollinose fasciae. 3 



mm. (N. J., Wise.*) pulchra Loew. 



Wings largely hyaline or subhyaline, marked with blackish spots about the 

 costal cell, the anterior cross-vein, the posterior cross-vein extending 

 to the third vein, and narrowly at the end of the second, third and 

 fourth veins 5- 



5. Abdomen shining black; on each side of the middle black spot of the 



wings is a white spot, the basal of which extends from the third to 

 the fifth veins, the outer from the third to the fourth veins. 2—3.5 



mm. (Alaska, Wash.,* Id.,* Or.) eluta Loew. 



Basal segments of abdomen fasciate with white pollen ; outer white spot 

 of wing not present. 3 mm. (Eur.; N. J., Ohio.) . .nebulosa Fallen. 



Diastata modesta new species. 



Female. — Length 2.5 mm. Disc of mesonotum brownish pollinose, the 

 notopleural suture and pleurae cinereous ; abdomen subshining, with uniform 

 thin coating of brownish pollen. Front luteous, the orbits raised as far as 

 the foremost bristle, merging at the minute hindmost frontal bristle with the 

 brown-cinereous color of the occiput. Postvertical bristles large, twice as far 

 apart as the ocellars. Antennae yellow, the third joint one and one fourth 

 times as long as broad, apically rounded, the black arista loosely plumose, and 

 about two times as long as the joint. Face and cheeks white. Two dorso- 

 centrals, eight rows of acrostichals, three supra-alars, two sternopleurals, meso- 

 pleuras setulose with a row of six upward-directed bristles along the posterior 

 margin. Legs including the coxae yellow. Wings nearly hyaline, the costal 

 cell black, the costal portion lightly infumated, no fasciae or spottings ; ante- 

 rior cross-vein located under the end of the first vein, costal spines minute. 



