Kahl: The Dipterous Genus Leucophenga Mik. 369 



scutellar bridge, usually very minute and easily overlooked in the 

 DrosophilincB, though sometimes quite well developed, as for instance 

 in Stegana coleoptrata Scopoli and Leucophenga ambigua sp. nov. In 

 the Drosophilince the post-alar callus is ill-defined, but in the Diptera 

 Calyptrata, for instance the Tachinidce, it is well-developed, and it is 

 distinctly seen that the bristle at top of the transverse ridge belongs 

 to the post-alar callus. Osten-Sacken in his masterly work on chseto- 

 taxy^^ calls these two groups of bristles only supra-alars in the Diptera 

 Acalyptrata, but I have preferred to designate them by separate names 

 as above; if, however, the expression supra-alars alone is used for 

 these two groups of bristles, then it is necessay to clearly define their 

 position, and it is not sufficient to merely say "two, three, etc. supra- 

 alars present," because it is of no small importance to know whether 

 or not there exist any bristles, large or minute, between the one at 

 the top of the transverse ridge, mentioned above, and the scutellum, 

 inasmuch as some genera have a bristle there, while others do not. 

 For instance the genus Sepedon has none there, the genus Tetanocera 

 has one (both genera belong to the SciomyzidcB) . 



Presctdellar bristles: I have preferred to retain this expression for a 

 well-developed pair of posterior acrostichals, usually situated some- 

 what nearer the scutellum than are the posterior pair of the dorso- 

 central bristles. 



First segment of abdomen: I apply this term to the small segment 

 below the basal declivity; in designating the color of the abdomen it 

 is necessary to define it from the second segment, which is the first 

 large segment. 



Genus Leucophenga Mik. 



Generic characters: Shape of head, thorax and abdomen as in true 

 Drosophila and Phortica, but the concavity of the upper occiput ap- 

 parently more evident than in Drosophila and in this respect more 

 like Phortica. Wings rather broadly ovate, more or less distinctly 

 pointed (indistinctly so in L. ambigua sp. nov.) with the casta reaching 

 only to the apex of the third longitudinal vein, ultimate section of fourth 

 vein gradually thinner towards apex (L. ambigua sp. nov. somewhat 



Note: The exotic species at my disposal were received more or less improperly 

 packed in pill-boxes, and I have for that reason used the greatest caution in de- 

 fining the characters, and it has even been necessary to omit some, which I might 

 otherwise have employed. The types of L. argenteo-fasciata and L. ambigua were 

 received pinned and L. bislriala glued to a card. 



