1906.J 196 



33 (31) Upper row of frontal bridles concave in front ; third joint of antennse 

 fimali, round, and of a brown colour in both sexes. 



J 9 . Thorax and abdonion black ; halt ores black or yellow (in- 

 dependent of sex) ; wings li^'htly tinged willi yellowish-grey ; legs 

 black, fore legs and knees yellow or rusty, one of the spines is some- 

 times absent from the pair on the middle tibife, hind tibiae with four 

 bristles on the front or under-side. One of the commonest species 

 ocf urring all the year through. 2—2^ mm.— concinna, Mg. 



•34 (33) Upper row of frontal bristles convex in front ; third joint of antennx 

 black, large, and lemon-shaped in the male, smalt and round in the 

 female. 



g ? . Halteres always black ; wings deeply tinged with yellowish- 

 grey ; legs deep black, fore legs paler, hind tibiae with three or four 

 bristles on the outer side besides the four underneath ; both spines on 

 the middle tibiae always present. A larger and darker insect than 

 concinna. 2^— 3i mm.— crassicornis, Mg. 



35 (32) Hind tibiae ivith spines as usual. 



The two species have much in common : — In each the thorax is 

 black, the frons high and glossy, third joint of antennae rufous and 

 lemon -shaped, the broad palpi and large female proboscis bright 

 orange, and the tip of the middle tibiae furnished with two or three 

 short spines in addition to the usual one on the outer side and the 

 long inner spur. 



36 (37) Thin veins end in the margin (normal) ; halteres black. 



g 9 . Middle row of frontal bristles moderately concave in front ; 

 abdomen of male entirely black with the anal protuberance bright 

 orange, of the female yellow, except for a broad black patch on the 

 dorsum extending from the 1st to the 4th segment inclusive ; hind 

 tibifE with two spines, one at the end of the upper third, the other a 

 little beyond the middle. 4— 4^ mm.— abdominalis. Fin. 



37 (36) Thin veins stop short of the margin ; halteres whitish or yelloto. 



g 9 . Frons very narrow (narrower than in abdominalis), middle 

 row of frontal bristles deeply concave in front ; first abdominal seg- 

 ment whitish, the other segments black, but the end of the anal 

 protuberance in the male and the female ovipositor are yellow ; hind 

 tibiae with three spines, one below the other at equal intervals, the 

 lowest being just beyond the middle. 3 mm.— ahbreviata, v. Eos. 



38 (17) Middle tibix with three spines, a pair at or near the end of the upper 



third, and one {alivays large and loell developed) about the junction of 

 the middle and lower thirds. 



A single spine is present on the fore tibiae, the number on the 

 hind tibisD very variable. 

 39 (42) Thorax tvith two pairs of dorso-central bristles. 



In the two species the antennae, palpi, halteres and legs are yellow ; 

 scutellum with four bristles. 



