Sept., I9I3-] Melander: Synopsis of Diptera. 253 



Head wholly or mostly black; thorax at most lightly pruinose (if the 

 frontal orbits are yellow compare superciliosa) 22. 



19. Notum and pleura; pollinose, not shining; penultimate section of the fourth 



vein much shorter than the ultimate section of the fifth vein 20. 



Thorax shining, very lightly pollinose ; legs entirely black ; the penultimate 

 section of the fourth vein nearly as long as the ultimate section o£ 

 the fifth; four strong dorsocentrals ; calypteres and fringe yellow; 

 bristles of the head strong. 2 mm. (Mont.*) rutiliceps n. sp. 



20. Discal cell long and narrow, the anterior crossvein beyond the end of the 



first vein; knees sharply yellow ; four strong dorsocentrals ; five fronto- 

 orbitals; fringe of calypteres blackish; wings slender, the veins 



strong. 2-z mm. (Mont.,* Id.,* Wash.*) genualis n. sp. 



Discal cell shorter ; the anterior crossvein before the end of the first vein ; 

 legs entirely black ^^' 



21. Dorsocentrals strong. 2 mm. (Ent. News, XXIII, 463 (1912).) (Ind.) 



davisii Walton. 



Dorsocentrals weak, hardly longer than the notal setulae; last segment of 



5 abdomen longer than the second, third and fourth segments together, 



compressed, jet black. 2 mm. (Col.,* Id.*) auriceps n. sp. 



22. Black, the abdomen especially greenish; two dorsocentrals; the segments 



of the fifth vein 3:2; anterior crossvein at one third the length of 

 the discal cell. (D. C, Mass., Ga., W. Ind., Wise, S. Dak.) 



viridula Coquillett. 



No trace of metallic coloring; anterior crossvein near or beyond the middle 



of the discal cell ^^" 



23. Large bristly species, usually with five strong frontal bristles and with one 



or two dorsocentrals before the suture; front very broad and uni- 

 formly opaque; calypteres dark, with bushy black fringe; antennae 

 brown at base; basal cells separate. (D. C, Mass.,* N. Y., Fla., 



W. Ind., La., Col., N. Mex., Cal.) ^^tosa Loew. 



Less bristly species, not more than four dorsocentrals; antennae black; 

 calypteres white ^' 



24. Costa interrupted at the third vein or much thinned between the third and 



fourth veins; mesonotum lightly pruinose and subshining; usually a 



small dorsocentral in front of the suture 25. 



Costa continuing to the fourth vein; as far as known, the calypteres en- 

 tirely white and fringed with white hairs; rarely with four dorso- 

 centrals ' ■ 



25. Calypteres fringed with white hairs; costa entirely interrupted at the third 



vein, (nigripes Meigen.) 2° 



Calypteres fringed with white hairs; costa faint beyond the third vein; 

 discal cell moderately large; sections of the fourth vein 1:3, of the 

 fifth vein 3:2; front tibiae and all the tarsi sometimes brownish. 

 (Eur. ;* Id.,* Wash.,* Ore.*) reptans Fallen. 



26. Sections of fourth vein 1:3, of the fifth vein 3 : 2. (Eur. ;* S. Dak.,* 



Wash.*) nigripes var. cinerascens Macquart, Strobl. 



