DESCRIPTION OF THE SPECIES. 233 



last segment, towards its end, has several black bristles. Ovi- 

 positor flat, rather broadly truncate, hardly as long as the last 

 three abdominal segments taken together, blackish-brown or 

 black, with black pile. Front feet, as well as the entire fore- 

 coxae, clay-yellow; on the posterior feet the first joint of the coxae 

 and the femora are brownish-black, or dark brown, the second 

 joint of the coxae, the tip of the femora, and the entire tibiae and 

 tarsi are clay-yellow ; the under side of the front femora bears a 

 row of black bristles, while the under side of the posterior femora 

 is without them. Halteres infuscated. Wings large, rather 

 broad, with convex anterior and posterior margins; veins, with 

 the exception of the first longitudinal, without bristles ; the first 

 longitudinal vein turns, not very far beyond the end of the 

 auxiliary vein, in a sharp, rectangular fracture, perpendicularly 

 towards the margin of the wing, which causes the stigmatical 

 cell to assume a strikingly short and square shape; the second 

 longitudinal vein is rather distant from the anterior margin of 

 the wing and has a rather straight course, so that the marginal 

 cell, although rather broad, is attenuated towards its end ; the 

 third longitudinal vein is turned backwards towards its end, so 

 that the first posterior cell is somewhat attenuated at the end ; 

 the small crossvein is placed about the middle of the discal cell, 

 which becomes considerably broader towards its end ; the last 

 section of the fourth longitudinal vein has a wavy course; the 

 posterior crossvein is very steep and only very gently curved ; 

 the posterior angle of the anal cell is drawn out in a point in the 

 usual way. The picture of the wings has somewhat the appear- 

 ance of rivulets, and consists of conspicuous and rather well- 

 defined brownish-black crossbands, which come in contact almost 

 in the same way as in the European Acidia lychnidis Fab. (com- 

 pare Loew, Bohrfliegen, Tab. Ill, f. 4) ; the picture of the pre- 

 sent species differs, however, in the more considerable extent of 

 the black coloring on the basis of the wings; the black bands 

 leave two hyaline indentations on the anterior and three on the 

 posterior margin; these hyaline spots have, in a certain light, a 

 whitish reflection. The first of these spots on the anterior mar- 

 gin is a rectangular triangle, the hypothenuse of which begins on 

 the costa a little before the end of the first longitudinal vein and 

 runs as far as the anterior end of the small crossvein ; the second 

 hyaline spot, separated from the first by an almost perpendicular 



