14(3 311t. E. E, Al »1E> OX XEW DIPTEEOrS IXSECTS. [JaU. 17, 



first segment steely, with a tuft of black hairs projectiug from the 

 anterior angles, behind m hich is a tuft of yeUow hairs ; second 

 segment steely on the anterior third above, on the sides for more 

 than halfMay, and on the hind margin, the remainder of the 

 segment dull black, with a _vellow dot on each side ; third segment 

 steely on the lateral margins, and with a narrow transAcrse steely 

 band in front and beliind, elsewhere dull black, with four oval 

 yellow dots arranged in the form of a quadrilateral, the anterior 

 pair twice ns far apart as the posterior : fourth and fifth segments 

 steely on the lateral and posterior margins, elsewhere dull black, 

 and each with four oval yellow dots arranged as on the third seg- 

 ment ; genitalia small, concealed : the abdomen is broadly spatu- 

 late, expanding from the base of the third segment to the posterior 

 margin of the fourth, and coutractiug thence to the tip ; the 

 second segment is stout and cylindrical, with a fringe of hairs on 

 each side, yellow in front and black behind ; the remainder of the 

 abdomen is sparsely clothed with short appressed black pile. Legs 

 black, with short, close-fitting black pile : the tarsi flattened. 

 Wiwjs suffused with brown, with a darker area at the base, which 

 is paler towards the posterior margin, and extends a little beyond 

 the anterior cross-vein on the costal side : ululo' well-developed. 



Ega, Brazil (Bates) : one specimen. 



This species is allied to Bacclia adspcrsa, Fab., but is at once 

 distinguished by the iufuscation of the entire wing. The terminal 

 section of the fourth vein is also much more oblique in this species 

 than in B. adsjyersa. 



Baccha letissima, sp. n. (Plate IV. fig. 15, S •) 



(5 . Length 10| to n| mm. ; length of wing 6| to 7 mm. 



Metallic bronze-blacl; u'ith deacl-hlacJi marldnrjS on the cdidomoi ; 

 the latter rfreathj cdtenuated : wincjs very sJiort, infuscated ; ahdcE 

 rudimentari/. 



Face and clicel-s metallic steely black, clothed (except on the 

 tubercle) with cinereous pollen ; facial tubercle prominent. Front 

 with a pentagonal dead-black patch in the angle of the eyes, on 

 each side of which, when viewed from behind, is a shimmering 

 white dot ; front elsewliere and antenniferous process metallic 

 black, the latter with a flattened rugose area above. Vertical 

 triangle black ; the short pile on the front and vertical triangle 

 black. Antenna small ; the first two joints black, the third 

 brown, oval ; arista blackish brown. Occiput black, with silvery 

 pollen, and fringed with short whitish hairs. TJiora.r rather dull, 

 metallic bronze-black on the dorsum, shining metallic greenish 

 black on Ihe pleura; ; a narrow dead-black median stripe on the 

 anterior part of the dorsum, not extending beyond the region of 

 the transverse suture : on either side of this stripe the dorsum in 

 front is brow nish pollinose, when viewed from behind or from 

 the side. ScuteUum metallic black ; scutelkuu and dorsum finely 

 •punctate, almost bare. AhdomcH : first segment metallic steely ; 

 second segment steel}, witli a broad dead-black transverse band, 



