FLIES PARASITIC ON ANTS. 433 



black bristles at the tip ; on the cheeks are some short 

 black bristles. 



The thorax is grey or brownish grey, broad, not much 

 arched, the disk being nearly flat, and on the hinder 

 part absolutely concave ; on the disk there are no long 

 bristles, but a dense clothing of rather short black 

 bristles ; along the side of the thorax between the 

 humeri, the base of the wing, and the scutellum are 

 some long black bristles, and two on the thorax just 

 before the scutellum ; on each side of the scutellum 

 are two long bristles ; halteres dirty pale yellow ; 

 abdomen bare, dull black, with slightly yellowish 

 incisures ; ovipositor polished black, long, slightly 

 incurved and grooved. 



Legs pale yellow, including the coxae, clothed with 

 minute black bristles ; all the coxae with two or three 

 black bristles at the tips, the legs otherwise bare 

 excepting the spurs ; femora flattened and widened, 

 especially the hind pair, the hind tibiae also slightly 

 flattened and widened on the apical half ; middle tibiae 

 with a long spur inside at the tip, and hind tibiae with 

 a small one inside and a very minute one outside ; tarsi 

 longer than the tibiae, joints gradually diminishing in 

 length. 



Wings very slightly smoky, broad ; second thick 

 vein not extending half the length of the wing, thick- 

 ened, but not forked at its tip ; first veinlet with a 

 steady curve; second very slightly curved at base, 

 otherwise straight; third very slightly undulated; 

 fourth hardly visible at base, evident towards tip, very 

 slightly undulated ; costa bristly up to end of second 

 thick vein. 



This species is readily distinguished by its simple 

 second thick vein, channelled irons, small size, and by 

 the absence of bristles on the tibiae. 



It is parasitic on Lasiua niger. 



v p 



