136 MB. E. E. AUSTEK ON NEW DIPTEROUS INSECTS. [Jan. 17, 



species like B. ruhricosa, Wied., and B. conjuncta, Wied., in the 

 same genus as B. elongata, Fab., when, for instance, what Fallen 

 called Scceva hyalinata is distinguished generically from Sijrphus 

 ribesii, Linn., or when Ocypiamus, Macq., is allowed to retain its 

 independence. 



Gro^ip I. 



Baccha nubilipennis, n. sp. (Plate IV. figs 7, 9, c? 2 , and 

 Plate V. fig. 14, head oi 6 ■) 



S $ . Length : 6 12| to 14^ mm., $ 12| to 13| mm. 



Face and cheeks yellow, ^ith yellow pollen and pale yellow pile. 

 Cheeks in S sometimes narrowly blackish immediately below the 

 eyes. A prominent, rounded, and sharply-defined facial tubercle, 

 commencing halfway down the face ; sometimes an indistinct 

 brown stripe between it and the antennae. Antennce orange ; third 

 joint large, ovate, larger in the 5 than in the S • A very pro- 

 nounced anteuniferous process, shining black above, and orange- 

 yellow immediately above the base of the antennje ; the orange- 

 yellow area is larger in the $ ; the iDrojectiou is truncate and 

 flattened in front, and pilose on the sides only. Front in J 

 greenish black, with yellow pollen, and vertical triangle black ; in 

 5 shining black, with a narrow triangular area on each side in 

 front yellow poUinose. Pile on front blackish in S , yellowish in 

 $ , shorter in the latter than in the former. Occiput with a fringe 

 of pale yellow hairs. TJiorax shining black ; the collar of hair in 

 front pale yellow ; elsewhere nearly bare. Humeri and postalar 

 callosities brownish ; pleurce with a broad vertical stripe of golden 

 pollen in front of the suture ; the stripe has a reddish ground ; 

 pleurae behind the wings silvery pollinose. Scutcllum polished 

 dark brown on the disc, more or less yellowish, semi-translucent, 

 behind. General colour of the abdomen metallic black (bi'owner in 

 5 ), sometimes with a distinct bluish sheen ; the abdomen is 

 broadest in the fourth segment. The first segment has outstanding 

 pale yellow hairs on each side ; elsewhere the abdomen is clothed 

 with very short appressed black pile. First segment black, 

 browner and with an edging of yellow in the 5 ; second segment 

 with a yellow basal band, notched in the median line behind, and 

 with an interrupted brownish-yellow band near the tip, tiie latter 

 often scarcely visible in the S ; third segment with a conspicuoiis 

 transverse yelloiu band, occupying about the middle third of the 

 segment, but slightly nearer the base ; the remaining segments 

 wholly metallic black ; male genitalia small and concealed. Legs 

 orange-yellow ; posterior femora slightly darker, dark brown above 

 and below on the distal half, but orange at the tips ; posterior tibiae 

 reddish on basal third, then dark browu ; posterior tarsi dark brown 

 on basal two-thirds of first joint, then whitish yellow. Wings 

 infuscated, dark brown in the middle, and usually darker in the d 

 than in the $ ; in the 5 the wings show a faint secondary infusca- 

 tion at the tips, above the third vein ; an area at the base on the 



