20 PEOCEEDINGS OF THE NATIONAL MUSEUM vol.72 



when taken in connection with Brauer and Bergenstamm's. The lat- 

 ter mention the female, with flattened fore tarsi and smaller ©cellars 

 than the male ; I do not have this sex. 



Male. — Front at narrowest (vertex) 0.23 of head width. Front 

 a little prominent, slightly shorter than face, which is receding. 

 Head wider than high (48 to 37) ; vibrissae at oral mai:gin; facial 

 ridges bristly about half way; frontals descending to middle of sec- 

 ond antennal joint; no orbitals; frontal stripe wide. Parafacials 

 bare and silvery. One large pair of frontals reclinate; ocellars 

 large, proclinate. Antennae long, third joint broadest in middle, 

 three to four times the second ; arista with basal joints short, slightly 

 thickened for one-fifth its length. Palpi normal, yellow; proboscis 

 fleshy, short. Back of head slightly bulging. Thorax somewhat 

 damaged in both specimens, the disk nearly all black with broad 

 white lateral border before wings. Pleurae almost silvery. Chaeto- 

 taxy: acrostichal, 2 anterior (none just before suture), posterior 

 spoiled; dorsocentral, 3, 3; humeral, 3; posthumeral, 2; presutural, 

 1 large ; notopleural, 2 ; supraalar, 3 (middle one large) ; intraalar, 

 3 (the front one minute) ; sternopleural, 3 in a small triangle rather 

 far back; scutellum with 2 lateral (the posterior large) and one 

 rather long, depressed apical pair; disk with upright bristly hairs 

 and a few depressed ones behind. Post scutellum and hypopleurals 

 well developed. Calypters moderately large, pure white. Abdomen 

 narrow, shining black, the first segment nearly as long as the sec- 

 ond; second and third with broad basal silvery band, including 

 about half the segment above, less below; fourth segment wholly 

 shining black. First segment with a pair of large strong median 

 marginals; second the same; third with marginal row of same, but 

 the median pair, as in the preceding segments, is not very close to 

 hind margin; fourth segment with a marginal row placed as on 

 third. The larger bristles of thorax and abdomen are flattened 

 longitudinally at base, giving them a very stout appearance. There 

 are no true discals on the abdomen. 



Legs black, rather stout, front tarsi unusually so; all clnws and 

 pulvilli elongated. Middle tibia with three bristle.^ on cutor front 

 side, the intermediate largest; hind tibia with a few in-egular bristles 

 on outer side. 



Wing noticeably brownish, more so alonsr veins, tips rounded, first 

 vein hairy on its middle third, third vein hairy almost to small 

 cross vein; bend of fourth vein oblique, slightly rounded: first 

 ])osterior cell open in margin rather far before apex; third vein un- 

 dulating beyond small cross vein, widening the first posterior cell 

 near its middle. 



