DRTALID^E TRITOXA. 103 



occur in a greater or lesser measure on specimens the prevailing 

 color of which is black. Most specimens have the greater part 

 of the front brown, some reddish-brown ; the usual coloring of 

 the antennae, also, is more brown than black, especially towards 

 the basis. The pubescence of the arista is short, but distinct. 

 The front has on both sides a very narrow, the face a broader, 

 border of white pollen; the face, also, is slightly hoary with 

 white, which is not equally distinct in all specimens, nor from all 

 points of view ; it is most perceptible around the antennae. The 

 rather indistinct pollen on the thoracic dorsum forms two rather 

 broad parallel lines. The first segment of the flattened ovipositor 

 resembles in its nature the preceding abdominal segments, to 

 which it is closely applied ; it is clothed, like those segments, 

 with short, black hairs. The wings are strongly cuneiform 

 towards their basis, and towards their tip they are rounded in 

 such a manner that the extreme apex is much nearer the poste- 

 rior than the anterior margin ; the second longitudinal vein is 

 slightly wavy upon the first two-thirds of its course ; its strongest 

 curvature is just above the small crossvein ; the latter is rather 

 oblique; the posterior crossvein, on the contrary, is steep, almost 

 perpendicular, slightly bisinuated in the shape of an S. The 

 color of the wings is black ; only very immature or faded speci- 

 mens have it brownish-black ; the three usual crossbands have an 

 almost whitish tinge, and are very narrow; the first among them 

 is so oblique that it almost assumes the appearance of a longitu- 

 dinal stripe; it starts at the basis of the third posterior cell, 

 diverges gently and moderately from the fifth longitudinal vein, 

 becomes more and more attenuated and pointed, and ends already- 

 some distance from the posterior margin ; the second pale cross- 

 band, which likewise has a very oblique position, begins at the 

 tip of the costal cell, just before the end of the auxiliary vein, 

 and runs to the posterior angle of the discal cell ; it is percep- 

 tibly more arcuated on its anterior than on its posterior portion ; 

 the third crossband, running from the anterior to the posterior 

 margin, likewise has a very oblique position, although less so 

 than the second ; between the posterior margin and the third 

 longitudinal vein its course is straight; from there to the anterior 

 margin it is more and more arcuated ; the distance between the 

 third crossband and the apex of the wing is very large, as it 

 almost equals one-third of the length of the wing. In the imme- 



