1918] Dipterous Genus Drapetis Meigen 191 



41 Hind tibia; without long extensor bristles, but instead seriately bristly, 



hind metatarsi with an erect comb of seven bristles; halteies blackish; 

 four rows of acrostichals; first posterior cell widest before the end; 



tibial spur small ,■ ■.•■,•■•,■• ■, comata, n sp. 



Hind tibise with two or one long extensor bristles, hind metatarsi not 

 pectinate; halteres yellow ; ,: • • • ■ • • ; ^'^• 



42 Third and fourth veins converging, the first posterior cell widest before 



its tip- antennae dark; scutellum and metanotum yellow, four acros- 

 tichals; tibial spur small • ^nflexa, n. sp. 



Third and fourth veins not converging, the first posterior cell widest 

 before its tip; antenna; yellow ,' ' ' ' ; , ... .43. 



43 Mesonotum and pleura; largely black, the notopleural suture broadly 



yellow- dorsal" hairs long; tibial spur black; one extensor bristle on 



hind tibia;; upper orbits polished • .seminigra, n. sp. 



Thorax mostly or wholly yellow • ■/■■■;■■ 



44 Mesonotum with a median brown vitta, upper pleurae brown; front linear; 



tibial spur long vitatta, n. sp. 



Mesonotum and pleura; not vittate; front narrow, its sides convergmg 



below ■ ' ',■ 'iV r li i 



45. Hind tibise with a single extensor bristle; posterior half of the mesonotum 



with a large crescentic black mark ■ upsilon, n. sp. 



Hind tibia? with two extensor bristles; posterior part of the mesonotum 

 marked at most with a prescutellar spot • yw 



46 Pleura; with a large round subalar spot, a rounded prescutellar spot fused 



with the black scutellum; mesonotal hairs sparse; tibial spur strong 



but blunt •. ■ — ■ ■ ■■Pleurahs n. sp. 



PleurcB unspotted, mesonotum reddish, sometimes with black metanotum, 

 scutellum and prescutellar spot • V ' ' ' j ' 



47 Tibial spur blunt; third antennal joint conical, twice as long as broad; 



abdomen yellow apically; sections of the fourth vein proportioned 



1-3, of the fifth vein, 2.5 : 1 rectineura, n. sp. 



Tibial spur long and sharp; third antennal joint less than twice as long as 

 broad; abdomen often entirely black • • ■ 48. 



48 Middle tibi^ 9 not setulose, of c? at most microscopically setulose; 



scutellum reddish, mesonotal hairs sparse; length 1.5-2 mm. . . . . . .4J. 



Middle tibia; c? 9 setulose with black denticles within; scutellum black; 

 genitalia sometimes yellow; mesonotum hairy; sections of the fourth 

 vein, 1 -. 2.2; length 2-3 mm .••■•• v •-• V , ,T ■, -• ' ': ^^■ 



49 Sections of the fourth vein proportioned 1 : 4; abdomen black; occiput 



polished black, without pollen • AuteicoUis, n. sp. 



Sections of the fourth vein proportioned 1 : 2.2; abdomen black on the 

 middle segments only; occiput subshimng, coated with fine gray 

 pollen simphcipes, n. sp 



50 Occiput polished black, without pollen; front femora cT 9 without black 



setulaj below; third antennal joint yellow, arista slender; pygidium 



without pollen, shining ■,•■,■■■ ■/." ■-■ ■^^^'^''^' ^^- ^P' 



Occiput pollinose; third antennal joint darker than the basal joints. ... ol. 



51. Arista heavily pubescent, appearing half as thick as the third joint; 



bristles of the hind tibia; distant; lower part of the head yellow; 

 ■ second section of the costa longer than the fourth and but little 



shorter than the third •■■•■: fumea, n sp. 



Arista not thickly pubescent, less than half as thick as the third antennal 



52 FronTfemora'cf with "black seta; beneath, bristles of the hind tibi^ 



distant flavida W lUiston 



Front femora cT 9 with black flexor seta;, the bristles of the hind tibiae 

 close together , ■ (/^'«' f - «?■) ^3- 



53 Prescutellar dark spot present; wings three times as long as broad; 



occiput pollinose to the eyes /«'«- n. sp. and var. 



Prescutellar spot wanting; wings less than three times as long as broad. . . .M. 



54 Spur of the hind tibia; forming a long slender curved yellow hook; occiput 



pollinose to the eyes var. unguhfera, n. var. 



Spur of the hind tibi^ forming a large broad black lappet; upper occipital 

 orbits shining ; var. nigrocalcarata, n. var. 



