TACHYTRECHUS. 109 



elongated and slender hypopygium is pedunculated and of a black 

 color ; the long and narrow lamellae are of an equal breadth, black, 

 fringed with rather long black hairs ; the interior appendages 

 small, without hairs at the tip. 



Hab. Middle States. (Osten-Sacken.) 



5. P. cognatus Loew. 9 . — Obscure seneus, antennarurn rufarum 

 apice fusco, ciliis oculorum inferioribus pallidis, coxis anticis totis flavis. 



Dark bronze-colored ; the tip of the red antennae brown ; cilia of the in- 

 ferior orbit pale; fore coxae entirely pale. Long. corp. 0.15. Long, 

 al. 0.15. 



Of this species I know only the 9 , which is a little larger than 

 that of the preceding species, and is distinguished from it by the 

 paler antennae, by the hairs of the feathered arista being a little 

 longer, by the depression on each side of the suture of the thorax 

 which is dusted with white only in the interior corner, and by the 

 entirely yellow fore coxae. The specific distinctness cannot be 

 called in doubt. 



Hab. Middle States. (Osten-Sacken.) 



Gen. VI. TACHYTRECHUS. 



The vertical diameter of the strongly pubescent eyes is very 

 large, and, on that account, the head very high. The face is com- 

 paratively narrow, becomes gradually broader towards the mouth, 

 and reaches altogether the lower corner of the eyes. Palpi of very 

 moderate size, also in the female. The first joint of the antennae 

 hairy on the upper side; the third joint of moderate size, rounded 

 or ovate. Arista dorsal, with an almost imperceptible microscopic 

 pubescence or apparently bare. Cilia of the whole orbit particu- 

 larly long. Feet rather slender ; femora not very strong ; the fore 

 femora towards the basis a little thickened. The first joint of the 

 hind tarsi not bristly. "Wings comparatively small ; the last seg- 

 ment of the fourth longitudinal vein converges gradually towards 

 the third longitudinal vein, so as to reach the margin of the wing 

 only at a moderate distance from this vein and before the tip of 

 the wing ; upon its middle there is a more or less distinct flexure, 

 which is sometimes more considerable in the J* than in the 9, 

 but is never very strong. The hypopygium is entirely disengaged, 

 with lamelliform rounded exterior appendages of moderate size. 



