1910.] 



151 



13 (12) Abdomen not so banded. 



$ . Thorax and abdomen black ; frons fixlly \ broader than long, 4 large and 

 nearly equal snpra-antennal bristles, the npper pair wide apart and outside 

 an alignment with inner bristles of middle frontal row, under pair closely 

 approximated, palpi yellow, antennae fairly large ; wings nearly clear, veins 

 black, 1 not more than half as long again as 2 + 3, costa more than \ but 

 less than 4 wing length, fringe only moderately short ; legs from yellowish- 

 brown to almost black, fore tarsi somewhat thickened with the metatarsus 

 shorter than the 2 following joints, hind tibia3 very finely and thickly 

 ciliated; hypopygium large, produced on either side below into a point 

 armed with a bimch of 5 or 6 short hairs, ventral plate minute and yellow, 

 anal organ black, rather long and slender f mm. latifrons, n. sp. 



14 (5) Mesoplewrse bare. 



15 (20) Halteres yellow. 



16 (17) A largish species {\h mm. or more). First costal division more tJian 



twice as long as the other two. 

 ^ V ■ Thorax black, sometimes obscurely reddish ; abdomen entirely black, or 

 yellow underneath and with narrow yellow margins to the segments ; frons 

 black and slightly shining, rather broader than long, upper supra-antennal 

 bristles large, under ones much smaller— about i the size, antenna) black or 

 red, palpi pale yellow ; wings nearly clear in the darker and pale yellowish- 

 brown in the paler specimens, costa i wing length, 1 more than double 

 2 + 3, fringe only moderately short, outer branch of 2nd thick vein 

 incrassated, angle at fork large ; legs very variable, from yellow in the 

 pale forms to brown or almost black in the dark, tibial cilia distinct and 

 rather sparse ; male abdomen stoutish, hypopygium small, bare of bristles 

 and almost of hairs, ventral plate small and indistinct, anal organ short 

 and thick, black in the dark and yellow in the pale forms... 



1^ — If mm. pygmsea, Zett. 



17 (16) Small species (under 1 mm.). First costal division only half as long 



again as the other two. 



18 (19) Halteres yellow and yellow stalked. Hypopygium without bristles. 



<? . Thorax and abdomen black ; frons black, ^ broader than long, upper supra- 

 antennal bristles fairly large and approximated, under ones directly under- 

 neath them and much smaller, antennae black, palpi yellow ; wings tinged 

 with yellowish-brown, thin veins dark and strong, costa barely more than 

 i wing length, fringe only moderately short, angle at fork moderate ; legs 

 yellowish-brown, fore tarsi rather longer and more slender than usual, 

 cilia on liind tibiaj fine and delicate ; male abdomen stovit, hypopygium 

 small and prolonged behind into a sort of snout, a few fine hairs but no 

 bristles, the large and dusky ventral plate broad but with a pointed end, 

 anal organ yellow, of moderate size and proportions and with a jaunty 

 upward tilt f mm. or rather more, lata, n. sp. 



19 (18) Halteres pale yellow and black stalked. Hijpopygium with a small 



bristle at each hind corner. 



N 2 



