20 6 NORTH AMERICAN TRYPETINA. 



I possess but a single specimen of this species. Its coloring 

 is not fully developed, although otherwise its preservation is per- 

 fect. It is black, with a distinct brownish tinge ; its abdomen is 

 more pitch-brown and rather shining. Head pale yellowish, with 

 a narrow dark yellow front and more ochre-yellow antennae; the 

 third joint of the latter is narrow and rather long, rounded at the 

 end ; the slender arista is dark brown, with a short, although 

 distinctly discernible pubescence. The usual frontal bristles are 

 black; behind the ocelli, however, near the lateral margin, two 

 shorter, whitish bristles are placed. Oral opening large, broader 

 than long. Palpi and proboscis pale yellowish, with a pale 

 pubescence ; the former do not project beyond the anterior edge 

 of the mouth, the flaps of the latter somewhat prolonged. The 

 thoracic dorsum shows four rather narrow longitudinal stripes, 

 formed by a whitish pollen; these stripes, arranged in pairs, are 

 confluent anteriorly ; the outside stripes are moderately abbre- 

 viated before the posterior margin of the thorax; the inside 

 ones reach only as far as the anterior pair of bristles, inserted 

 upon the longitudinal middle of the thorax ; each of the bristles 

 of this pair is placed between the end of the corresponding 

 inside stripe and the outside one; the inside stripes are 

 separated by a broad dark interval, which shows the shining 

 brownish-black color of the remainder of the thorax. When the 

 thorax is viewed from the front side, the light falling in from 

 behind, the pollinose stripes appear somewhat more broad ; the 

 interval between the inside stripes appears somewhat nar- 

 rower and a little more opaque ; at the same time, this point of 

 view discloses upon the outside stripes and upon the margin of 

 the inside ones, alongside of them, some short, snow-white 

 pile, while the remaining pile of the thoracic dorsum is black. 

 The humeral callosity and a stripe running from it to the root 

 of the wing, is white. The rather flat scutellum is white, 

 blackish on the sides and at the basis. The bristles of the thorax 

 and the four bristles of the scutellum are black. The first four 

 segments of the abdomen have each, on the posterior margin, a 

 rather uniformly broad crossband, formed by whitish pollen ; the 

 last segment, which has no such band, is paler brown along the 

 posterior margin. The comparatively scattered and not very- 

 short pile on the abdomen is black; it is white only on the pale 

 crossband on the posterior part of the first segment. The bristles 



