148 MR. E. E. AUSTEN ON NEW DIPTEEOUS INSECTS. [Jan. 17, 



vestige o£ a tubercle, clothed with pale \Ahitish pile, and cinereous 

 pollinose on the sides. Front metallic blue at the sides, bronze- 

 black in the middle, clothed with blackish pile ; the apex of the 

 angle of the eyes and a narrow' margin on each side cinereous 

 pollinose : anteuniferous process not prominent. Antennce yellow, 

 small ; thii'd joint some\\hat oblong in shape, rounded at the tip, 

 which, ^^^th a rather broad upper margin, is bro\vn. Occiput 

 cinereous, fringed with silvery hairs. Thorax and scutellum 

 metallic bronze-browTi, the latter steely on the hind margin ; 

 pleurae bronze antei-iorly, pale metallic bluisli white behind the 

 base of the wings ; post-alar callosities reddish : thorax sparsely 

 clothed \^'ith very short dark pile, the scutellum with longer 

 pale pile. Abdomen slender, spatulate, steely on first segment, 

 elsewhere broMu ; the typical specimen has a narro\A' transverse 

 faiut yellow band, widely divided in the middle, at the base of 

 the fourth segment ; genitalia small, concealed : a tuft of whitish 

 hairs on each side of the first segment, and the second and third 

 segments with a fringe of shorter pale hairs on each side ; the 

 abdouien elsewhere nearly bare. Anterior legs yellow, the third 

 and fourth joints of the tarsi, and the outer side of the femora 

 toA^ards the base, broA^Tiish ; second and third pairs of legs brown, 

 the bases and tips of the femora, the basal thii'd of the posterior 

 tibiae, the whole of the middle tibise, the first two joints of the 

 middle tarsi, the tip of the first and the whole of the second joint 

 of the posterior tarsi, pale yellow : the middle femora with a 

 fringe of rather long pale hairs behind ; the posterior femora with 

 a similar but shorter fringe of hair on the outer and inner side. 

 Third longitudinal vein of the A^ing straight. 



Brazil, region of the Amazon (Bates) ■ two specimens, both 

 males. 



This species is not closely allied to any other known to me ; in 

 the markings of the M-ings it resembles B. higoti, which, however, 

 distinguishes itself at once by the reddish colour of the basal half 

 of the abdomen, as also by the rudimentary condition of its alulte. 



Baccha pitmila, sp. u. (Plate V. fig. 12, c? .) 



J 2 . Length 6g mm. 



Tellow, shining : centre of dorsum of the thorax shining blach^ 

 u'ith th-ee cinereous pollinose stripes; abdomen contracted, but yet 

 stout, at the base, then spatulate; vAth dark broivn cross-bands and 

 lineate marl-ings. Legs yeUoiu ; posterior femora in the S with 

 the basal third and a band near the tip, posterior tibic with a fainter 

 band near the base, broivn ; these markings are much fainter in the 

 5 . and in another S the extreme base of the posterior femora is 

 iielloiu. Wings hyaline ; subcostal cell brown : alul(e rudimentary. 



Face and cheeks pale opalescent yellow, a narrow shimmering 

 white border next the eyes, when the face is viewed from above ; 

 facial tubercle relatively large, at least in the S , rounded ; in the 

 cJ , frontal triangle and anteuniferous projection pale shining 

 vellow" with a black dot above the base of the antennae ; vertical 



