1906.] 



263 



48 (49) Middle tihix toith three spines, a pair in the upper third and the other at 



the junction of the middle and lotver thirds. 



J ? . Thorax, abdomen and halteres black ; meso-pleurse with 

 numerous short bristly hairs and one long conspicuous bristle ; frons 

 glossy, about as high as broad ; female proboscis elongated ; wings 

 yellowish-brown, second thick vein with several distinct bristles at the 

 inner end, first thin vein deeply curved at its origin ; legs black, the 

 front pair paler and all the knees yellow ; hind tibise with two large 

 spines, both on the outer side, one at the end of the upper third, the 

 other close to the tip. 3-3^ x-am.-mordellaria. Fall. 



49 (48) The third spine on the middle tibia; close to the tip, on the outer side. 



50 (53) Frons with a large knob or hump on the vertex ; the third spine on the 



middle tibiae strong. 



Both are stout, heavily built species, with the thorax, abdomen 

 and halteres deep black ; the frons narrow (at least as high as broad) ; 

 the antennce unusually small ; legs deep black, the front pair and all 

 the knees yellowish, the femora, especially the hind pair, very stout, 

 the hind tibiffi widened towards the tip, and the hind metatarsi 

 thickened ; armature of hind tibiae as in mordellaria. 

 51 (52) Fore tibix with two to four spines in a row. 



S ? . Frontal knob broad, occupying at least half the width of 

 the frons ; third joint of antennae red or reddish, round ; palpi black ; 

 hind margin of 1st abdominal segment broadly whitish, usually sending 

 two triangular prolongations of the same colour on to the dorsum of 

 the segment ; costa darkened and thickened on the outer end, fringe 

 very thick and short ; second thick vein armed with numerous small 

 setEe ; first and second thin veins much wider apart on the wing 

 margin that at their origin (2 to 1) ; last joint of the fore tarsi in the 

 male normal. 3^ mm.-incrassata, Mg. 



52 (51) Fore tibix with only one spine. 



S ? . Frontal knob narrow, not more than one-third the width 

 of the frons ; third joint of antennae black, lemon-shaped ; palpi more 

 or less yellow ; hind margin of 1st abdominal segment black ; costa 

 not darkened or thickened on the outer end, fringe longer than in 

 incrassata ; second thick vein bare ; .. first and second thin veins not 

 much farther apart on the margin than at their origin (IJ to 1) ; last 

 joint of fore tarsi in the male dilated and fringed with long hairs. 



2i mm. — carinifrons, Zett. 



53 (50) Frons without such knob ; third spine on middle tibiae weak. 



54 (55) Hind legs very stout, the femora, tihix, and metatarsi being as massive as 



in the two preceding species. 



$ . Thorax, abdomen and halteres black ; frons shining, mode- 

 rately broad ; palpi rather large, black, and with strong bristles 5 

 wings lightly tinted with grey, thin veins fine but distinct ; second 

 thick vein ends in a prominent oval smooth swelling, from the base of 



