loi MK. E. E. AUSTEX Oy ^ESY piPIEROTTg INSECTS. [Jan. 17, 



posterior fifth ; third segment with a similar bro\\n transverse 

 posterior band, which, however, is concave anteriorly for about a 

 fourth of the w idth of the segment on each side of the median 

 line ; in the median line it is produced into a small angle, from 

 \\ hich a faint brown median stripe extends forwards to within 

 about one-seventh of the length of the segment from the anterior 

 margin ; fourth segment w ith the extreme hind margin and three 

 triangles brown ; two of the triangles are lateral in position, one 

 in each ])osterior angle, and extend forwards and inwards to alwut 

 tlie middle of the segment ; the third is median, and narrower 

 than the other two, and is prolonged as a median stripe to the 

 anterior margin, before reaching which, however, it becomes faint ; 

 the markings on the fifth segment are similar to those on the 

 fourth, but narrower, and the lateral triangles are so prolonged 

 that they are only narrowly separated from the anterior margin ; 

 the median triangle, too, is here represented by a stripe, which, 

 while expanding slightly posteriorly, is only about half the \\idth 

 of the median stripe on tlie preceding segment, and (in the typical 

 specimen at least) is separated by about one-eighth of the length 

 of the segment from the anterior margin ; on the short sixth seg- 

 ment the lateral triangles (here almost reduced to stripes) reach 

 the anterior margin without becoming indistinct, while the median 

 triangle is represented by a small, but sharply defined, triangular 

 spot, with its base in the centre of the anterior margin and its apex 

 in the middle of the segment. The third longitudinal vein of the 

 wings is nearly straight, and only slightly concave posteriorly ; 

 distal half of subcostal cell dark ochraceous ; knobs of halteres 

 ferruginous. 



Brazil, region of the Amazons (Bates): one specimen. 



In the markings of the abdomen this species somewhat resembles 

 B. f/ilva, but is at once distinguished by the colour of the dorsum 

 of the thorax, as well as by the deeper colour of the scutellum and 

 abdomen, and by its larger size. 



Baccha gilva, sp. n. (Plate Y. fig. 7, d •) 



S . Length 9^ mm. 



Pale yellow: tJiora.v metallic broivn in centre of dorsum, abdomen 

 with hrown transverse bands and other marl-ini/s ; the abdomen is flat, 

 broad, not contracted at the base, but e.c])andln(i reijularhj to the hind 

 margin of the fourth segment. Wings ivith a yellowish tinge, especially 

 towards the base ; veins yellow, the auxiliary and flrst longitudinal 

 veins orange : alulce rudimentary. 



Face and cheels pale yellow, shining, the low facial tubercle dull, 

 the face receding. Front yellow, with a black dot on the anterior 

 face of the anteuniferous projection ; the front clothed with brown 

 pile, the upper part of the face below the antennae also with 

 darkish pile ; vertical triangle elongated, tliough not very narrow, 

 cinereous pollinose, the ocelli remote from the vertex ; occiput 

 fringed at the sides with golden yellow hairs. Anfennee orange, 

 third joint I'ounded ; arista brown, yellow at the base, Thora.c 



