SOUTH AMERICAN DIPTERA. 283 



black. Legs black, their pile short, white ; the knees and more or less of the 

 base of the tibiae reddish ; hind femora much thickened. Wings hyaline, a small 

 stigmatic spot. 



One specimen, Chapada. 



78. Erisfalis albifrons Wiedemann; Roeder. Stett. Ent. Zeit. 1865, 340.— 



Brazil, Porto Rico. 

 Eristalis albiceps Macquart, Dipt. Exot. ii. 2, 56, 41 ; Williston, Synopsis N. 



A. Syrphidaj, 172. 

 Eristalis seniculus Loew, Centur. vi. 63. 



One specimen, S , Rio de Janeiro. 



79. Pteroptila milesoitles Bigot. 



Three specimens, Chapada. The description leaves no doubt of 

 the identity. 



80. Pteroptila simplex Schiner, Nov. Exped. 365. 



Six specimens from Chapada agree essentially with the description. 

 The third joint of the antennae is sometimes red, and the liind femora 

 below are more or less red. The species is closely allied in appear- 

 ance and structure with the following, but will be at once distin- 

 guished by the slender median dorsal stripe being gray, not com- 

 posed of yellow tomentum like the other markings of the dorsum ; 

 by the much less thickened, almost wholly black hind femora, etc. 



81. Pteroptila seinula u. sp. 



% . — Length 15 mm. Eyes bare, narrowly contiguous ; frontal and vertical 

 triangles black, the former white pubescent on the orbital margin. Face thickly 

 whitish pollinose, a broad median stripe and the cheeks, shining black. Autennse 

 brownish black, the arista luteous; third joint oval, not transverse. Posterior 

 orbits densely light yellow pollinose. Thorax black, but very little shining ; the 

 mesonotum with a slender median stripe and the narrow posterior margin, a 

 slender strigula on each side on the suture (not quite reaching the median stripe) 

 and a slender oblique spot on each side behind the humeri, all opaque yellow to- 

 mentose. Pleurae with a slender whitish pollinose vertical stripe. Abdomen 

 opaque black ; third and fourth segments opaque reddish yellow, due to short, 

 dense, recumbent pile; third segment with a broad, bare, black, median band; 

 third with the narrow front margin, and a slender transverse band of the same 

 black ; hypopygium densely yellowish pollinose. Legs black, the distal half of 

 hind femora, and the hind tibiae, except their tip, reddish yellow ; all the tarsi 

 brownish red ; all the femora swollen, the hind pair extraordinarily so on the 

 proximal two-thirds. Wings nearly hyaline behind, brown or brownish along 

 the front margin ; sixth vein strongly sinuous. 



Two specimens, Chapada. 



