MR. F. WALKER ON DIPTERA COLLECTED aT 
20. Ommatius retrahens, Walk. See Vol. III. p. 88. 
21. OMMATIUS PLATYMELAS,n.s. Fem. Niger, latus, fronte aurata, 
thoracis lateribus subauratis, scutello cinereo, abdomine subplano, 
segmentorum marginibus posticis maculisque lateralibus trigonis 
cinereis, tibiis rufis apice nigris, alis nigris nigricante marginatis. 
Female. Black, broad, stout ; head clothed beneath with white hairs, 
gilded in front ; epistoma flat; mystax extending to the base of the 
antennze, composed of black bristles and of a few inferior white 
bristles ; thorax slightly gilded on each side; scutellum cinereous; 
pectus hoary ; hind borders of the segments and underside with cine- 
reous tomentum, which forms triangular spots along each side; legs 
very robust, with black bristles; tibiz red, with black tips; wings 
black, blackish towards the tips and along the hind border ; halteres 
pale yellow. Length of the body 6 lines ; of the wings 11 lines. 
Fam. LEPTIDA, Westw. 
Gen. Suragina, Walk. 
22. SURAGINA SIGNIPENNIS,n.s. Fem. Nigra, thorace vittis duabus 
lateribusque canis, abdomine cano lanceolato apicem versus com- 
presso, femoribus apice fulvis, tibiis rufescenti-piceis, alis cinereis 
fasciis duabus maculaque interiore nigricantibus, gutta adhuc interiore 
nigra. 
Female. Black; head with whitish tomentum behind and beneath ; 
thorax with two hoary stripes, which are dilated and united hindward ; 
sides and pectus also hoary; abdomen hoary, lanceolate, compressed 
towards the obtuse tip, nearly twice the length of the thorax; legs 
long, slender ; femora with tawny tips; tibize reddish piceous; wings 
cinereous, with two blackish bands, which are united on the costa and 
are separated obliquely hindward, second band apical; a blackish 
elongated subcostal spot near the inner side of the first band, and a 
black discal dot still nearer the base; halteres yellowish towards the 
base. Length of the body 6 lines; of the wings 12 lines. 
Fam. BOMBYLIDA, Leach. 
Subfam. TuErEvites, Walk. 
Gen. TuErnva, Latr. 
23. THEREVA cCoNScITA, n. s. Mas. Nigra, argenteo tomentosa, 
thoracis disco nigro vittis duabus interlineatis canis, abdomine fasciis 
sex nigris, alis cinereis apices versus nigricante nebulosis. 
Male. Black, with silvery hoary tomentum; head silvery white in 
front ; 3rd joint of the antennz lanceolate, nearly as long as the 1st 
and 2nd together; arista extremely short; disk of the thorax black, 
