August, 1908. 1 



169 



2 (I) Supra-antennal bristles depressed, directed forwards towards the mouth 



{normal). 



3 (1) Scutellum with six strong and equal bristles. 



£ ? . Thorax, abdomen, and halteres black, meso-pleurse with one or more long 

 bristles and other shorter ones; frons barely half as broad again as long, supra- 

 antennal bristles large and equal, the under pair close to the middle line, palpi 

 yellow ; wings tinged with yellowish-brown, fringe very short, costa to middle 

 of wing, 1 nearly three times as long as 2, first thin vein leaves at the fork, 

 runs a nearly straight course and is slightly recurved at the margin ; legs 

 blackish-hrown ((?), yellowish-brown (?), hind femora dilated, tibial cilia 

 distinct though short ; male abdomen slender, hypopygium large and grey, no 

 lamella, the shining black ventral process very large, of irregular shape, curving 

 round the subanal body (which, when exposed, is also shining black) from left 

 to right, the long anal process is yellow with a black base... 



2j — 3 mm. sexspinosa, Coll., ms. 



4 (3) Scutellum with only four bristles. 



5 (10) Cilia on middle and hind tibite in a double row, one on each side the seam ; 



those of the inner row on hind tibise very large, of the outer much 



smaller. 

 The three species are very similar. They are large and robust insects with bare 

 meso-pleuraa and yellow halteres ; the frons nearly as broad as long, the inner 

 bristle of lower frontal row almost vertically underneath the outer one, supra- 

 antennal bristles large and equal, the upper pair set wider apart than usual ; wings 

 brownish-yellow, fringe very short, angle formed by the forking of thick vein acute, 

 first thin vein recurved at margin (slightly in picta) ; legs yellow, hind femora 

 dilated and blackened at the tip, front tibia? ciliated with fine and small bristles on 

 upper edge ; sides of second abdominal segment projecting and surmounted with 

 a row of bristles ; hypopygium provided with symmetrical lamellae, subanal body 

 concealed, anal protuberance long and cylindrical. 



6 (7) First costal division not greatly longer than the second. 



$ ? . Thorax and scutellum yellow or reddish ; frons yellow, antennas orange, palpi 

 pale yellow armed as usual (Becker says bare or nearly so) ; costa thin, reach- 

 ing beyond middle of wing, fringe fine and open, first thin vein, barely recurved 

 at margin ; abdomen ( $ ) yellow beneath, black above with narrow yellow 

 hind margins to the segments and a series of yellow triangular marks clown 

 the centre, extending the whole length or limited to some of the hinder 

 segments, (?) as in the male, or entirely black with only the hind margins 

 pale ; lamellae of hypopygium yellow, small and rounded... 



2j mm. picta, Lehm. 



7 (6) First costal division greatly longer than the second (twice or more than 



twice as long). 



8 (9) A pair of small, curved and blunt-ended spurs beneath the end of the anal 



protuberance of the male. First abdominal segment of female mainly 

 yellow, at least the front and hind margins pale, sometimes entirely 

 yellow. 



