144 D1PTERA OF NORTH AMERICA. [PART III. 



margin, and hence gray and opaque; the last segment is similar 

 to the penultimate, only the dust on the posterior margin is less 

 extended. The female has a blackish-gray abdomen (its color- 

 ing, however, seems to have been unnaturally modified in the 

 four specimens which I had for examination) ; at the basis of the 

 last three segments a darker coloring is perceptible, but it is not 

 shining. The flattened, broad, yellowish-brown ovipositor is but 

 very little attenuated towards its end. Feet brownish-yellow, 

 the front femora at the basis, the four posterior ones near the 

 apex, brown. The more maturely colored male has the greater 

 part of the femora dark-brown, the first half of the tibiae and a 

 faded ring upon the middle of their second half, yellowish-brown. 

 Wings comparatively long and narrow; the first longitudinal vein 

 reaches far beyond the middle of the anterior margin and is beset 

 with bristles along the side of the very long stigma only ; the 

 longitudinal veins have a very irregular undulated course; both 

 crossveins have their anterior end nearer to the root of the wing, 

 than the posterior end; their position is consequently a distinctly 

 oblique one and both are slightly bisinuated; the third longitu- 

 dinal vein is not beset with bristles. Both small basal cells are 

 rather large in size ; the posterior angle of the anal cell is strongly 

 pointed ; the third and fourth longitudinal veins are parallel 

 towards their end. The stigma is brownish-black ; a brownish- 

 black picture is contiguous to it, which has almost the shape 

 of an inverted Y ; it is formed by two crossbands which are 

 coalescent in front; the first is broader and runs from the basis 

 of the stigma over the basis of the discal and of the third poste- 

 rior cells rather perpendicularly, almost reaching the posterior 

 margin of the wing, while the narrower second band takes an 

 oblique course over both crossveins, as far as the posterior 

 margin ; a short, but rather broad brownish-black crossband runs 

 from the humeral crossvein as far as the basis of the anal cell ; 

 upon the apex there is a very large blackish-brown spot, begin- 

 ning at the end of the marginal cell and extending to the tip of 

 the second posterior cell ; in the submarginal cell, between this 

 large spot and the preceding crossband, there is a brownish-black 

 spot of a considerable size, which, however, is very variable in 

 different specimens; the portion of the marginal cell situated 

 between the stigma and the apical spot has blackish-brown, 

 brownish and almost hyaline spots; a small spot of a much darker 



