FLIES PARASITIC ON ANTS. 433 



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 frons, small size, and by 

 the absence of bristles on the tibiae. 



It is parasitic on Lasius niger. 



Platyphora, n. gen. 



Lata, planx, tota absque setis. Frons latissima. 

 Thorax transversus. Abdomen parvus. Alarum vena 

 cubitalis simplex, subacostali parallela ; venulae undu- 

 latae ; costa ad basin subciliata. 



Distinguished from all the existing genera of 

 Phoridae by its flat and broad shape, which resembles 

 that of the small species of Sphcerocera. The absence 

 of strong bristles on the frons, thorax, and legs also 

 distinguishes it from all the genera except Gymnophora, 

 which, however, is of the usual arched PAo7'a- shape, 

 and has the cubital vein forked, costa bare, &c. 

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