156 MR. E. E. AUSTEN ON NEW DIPTEROUS INSECTS. [Jan. 17, 



the pleurse are shining metallic ; above the middle coxse a faint 

 brownish opalescent stripe extends upwards and backwards to 

 the metanotum, which is dark metallic. Scutellum wholly saffron- 

 yellow. Ahdomen flat, broad, not contracted at the base, but 

 expanding regularly to the end of the foiu-th segment ; like the 

 thorax, it is almost bare ; first segment pale yellow , with a tuft 

 ot" yellow hairs on each side ; second segment with rather more 

 than the basal third brown, narrowly yellowish at the extreme 

 base, and with a shining reddish-brown band on the hind margin, 

 in front of which is a narrow dark brown transverse band, 

 which is slightly concave posteriorly ; the yellow area of the 

 segment therefore takes the shape of a fairly broad ti-ansverse 

 band ; the brown basal area is sometimes fainter, and the seg- 

 ment then appears yellowish at the base also ; third segment 

 shining reddish brown on the posterior margin, in front of which 

 is a narrow transverse brown band, which projects on each side 

 into a small angle at about a fifth of the width of the segment 

 from the lateral margin ; from the aiiterior margin a brown spot 

 shaped like a spear-liead projects backwards in the median line, 

 and is narrowly connected by an almost obsolete median stripe 

 with the posterior transverse band ; from the anterior third of the 

 lateral margin a tongue-shaped brown mark projects inwards on 

 each side, leaving the actual anterior margin of the segment 

 yellow ; on the fourth segment tlie markuigs are a modified repre- 

 sentation of those on the third ; there is a narrow shining brown 

 posterior border, \\ hich expands into a dull brown quadrate area 

 on each side, from wliich a greatly prolonged acute angle projects 

 forwards and sliglitly inwards, extending to \\ ithin one-fourtli of 

 the length of the segment frem the anterior margin ; the median 

 line is occupied by a fairly broad and sharply defined stripe, wliich 

 expands at each end, but the tongue-shaped mark which is seen 

 projecting inwards on each side of the preceding segment in front 

 is here much reduced and sometimes almost obsolete ; the width 

 of the yellow marks on this segment varies in different specimens, 

 and in the typical individual those on either side of the median 

 stripe extend to the hind margin ; the markings on the fifth 

 segment are arrived at by a still further modification of the fore- 

 going ; in this case the brown marks take the form of a median 

 stripe, expanded towards each end, and of a curving piece pro- 

 jecting forwards from each posterior angle and nearly reaching to 

 the anterior margin ; the lateral margins of the segment are also 

 narroA\ly brown ; the sixth segment, ^\ hieh is very small, is 

 brownish on each side, and has a narrow median stripe extending 

 almost to the hind margin ; the brow n marks are, however, not 

 visible in the typical specimen. Third longitudinal vein of the 

 wings straight, curving downwards at the tip. 



Brazil, region of the Amazons (Bates) : two specimens. 



In addition to the above, there is also in the collection a small 

 male, which I regard as belonging to this species ; it is, however, 

 too much damaged to describe, and I have therefore made a fem ale 



