106 D1PTERA OF NORTH AMERICA. [PART II. 



hairs. Arista towards the tip with short feathery hairs. Cilia of 

 the inferior orbit black. The spot on each side near the transverse 

 suture of the thorax is covered with white dust, however this dust 

 is not distinctly seen in every direction ; the usual deep-black 

 stripe-shaped double spot immediately above the root of the wing 

 becomes distinctly visible, when looking at the thorax from be- 

 hind ; likewise the usual little white spot in the neighborhood of 

 the hind corner is seldom distinctly seen and is always very small. 

 On the posterior margin of the thorax there is no spot with white 

 dust. Scutelluin bluish-black with velvet-black lateral corners. 

 In well preserved specimens there is a middle-stripe with grayish- 

 white dust. Pleurse black, gray on account of a thin whitish 

 dust. Abdomen bronze-black, each segment on the lateral margin 

 with a small spot covered with white dust and not visible in every 

 direction. Fore coxae brownish-yellow, with an almost imper- 

 ceptible, very thin covering of white dust. Middle and hind coxas 

 black. The color of the feet is rather variable ; usually they are 

 yellowish-brown, the upper side of the anterior femora, the tip of 

 the hind femora, likewise all the tibias and tarsi black-brown ; 

 nevertheless there are specimens in which they are more of a 

 brownish-yellow color and where the tip of the femora and the 

 tarsi, with the exception of their roots, are blackish-brown, while 

 the upper side of the tibise is indistinctly spotted in consequence 

 of the brownish color of the places of insertion of the bristles. 

 Cilia of the tegulse black. Halteres blackish. Wings rather 

 small, narrowed towards the basis, distinctly blackened, darker 

 towards the anterior margin ; in more faded specimens dark mar- 

 gins appear around the veins, as is also the case in the other 

 species of the same genus. 



Hob. Trenton Falls, N. Y. (Osten-Sacken.) 



3. P. laetus LOEW. % . Viridis, ciliis oculorum inferioribus nigris, 

 fronte et dimidio thoracis posteriore violaceis, alis ex fusco cinereis. 



Green, cilia of the inferior orbit black ; front and hind part of the thorax 

 violet ; wings brownish-gray. Long. corp. 0.12 0.13. Long. al. 0.12 

 0.13. 



SYN. Pelastoneurus Isetus LOEW, Neue Beitr. VIII, 38, 3. 



Dark-green, rather shining. Face considerably broad and 

 covered with a dense snow-white dust, the inferior third convex. 



