TO DIPTERA OF NORTH AMERICA. 



5. T. unicolor LOEW. . (Tab. II, fig. 6.) Flava, tboracis vittis 

 scutelloque nuilto pallidioribus, fasciis alarum fusco-flavesceutibus, pos- 

 tice divergentibus, vena longitudinal! tertia setosa. 



Yellow, the stripes of the thorax as well as the scutellum much paler ; the 

 brownish-yellow bands of the wings diverging posteriorly ; the third 

 longitudinal vein with bristles. Long. corp. 0.26. Long. al. 0.27. 



Rather pale yellow. Front a little brighter, of moderate breadth ; 

 frontal bristles black, the superior ones rather stout. The yel- 

 lowish antennae are nearly as long as the face, bristle very short, 

 beset with a very short and delicate pubescence. Face a little re- 

 ceding, the furrows for the reception of the antennas proportion- 

 ately rather deep. Opening of the mouth rather widened, border 

 of the mouth sharp. Proboscis rather thick, with the suctorial 

 flaps slightly prolonged ; palpi broad. The upper side of the 

 thorax, above the base of the wings, shows a stripe running from 

 the suture to the posterior border of the thorax, and has in the 

 described specimen rather a whitish color, which seems to have 

 been pale yellow in the living insect; of the same color are the 

 shoulder and the space behind it, the scutellum and a large spot 

 above the poisers ; a broad stripe of the same color seems to run 

 from the middle of the posterior border of the thorax to nearly its 

 middle. The dark stripes usual in other species are indicated by 

 rows of blackish spots; they may, however, have become visible 

 only after the drying up of the insect. The short hairs of the thorax 

 are pale yellowish, the bristles black. Scutellum with four black 

 bristles. Metanotum with a black stripe on each side. Abdomen 

 with pale, very short hairs and brownish-black bristles at its end ; 

 last segment a little prolonged, with an indistinct brown longitu- 

 dinal line on each side. Legs yellow; anterior femora with some 

 brown bristles on their under side. Wings rather large; the bauds 

 are brownish-yellow with brown edges, entirely brown near the 

 posterior border and the tip of the wing; the clear spaces which 

 they leave are as follows : 1. A very oblique one, interrupted on 

 the third longitudinal vein, with its anterior end forming a trian- 

 gular spot, placed beyond the tip of the first longitudinal vein, 

 and running through the base of the discal cell as far as the base 

 of the posterior basal cell ; 2. A band, having the form of an S, 

 rising on the posterior border, near the tip of the last longitudinal 

 vein, and, after running between the transverse veins, ascending as 

 high as the second longitudinal vein, from whence it turns again 



