76 DIPTERA OF NORTH AMERICA. [PART III. 



is also more intense along the costal margin, than upon the re- 

 maining surface. 



Hab. Carolina (Zimmerman); Washington, D. C, New York, 

 Illinois (Osteu-Sacken) ; Massachusetts (Harris). 



Observation 1. — Mr. Macquart (Dipt. Exot. Suppl. I, p. 210) de- 

 scribes as Oxycephala maculipennis from Texas (figured on Tab. 

 XIX, f. 12), a species which either is a Pyrgota or is closely allied 

 to this genus. In several respects this species shows a decided re- 

 semblance to P. millepunctata, and the question as to their diver- 

 sity is a very doubtful one. The conformity is especially apparent 

 in the picture of the wings and the venation, also in the coloring 

 of the front and even in that of the thorax. But Macquart says 

 that the thoracic stripes are interrupted near the suture (which 

 is also rendered in his figure) ; moreover, according to the figure, 

 the posterior angle of the anal cell is drawn out in a much longer 

 point than is the case in P. millepunctata. These discrepancies 

 alone, however, with Macquart's well-known inaccuracy in de- 

 scription and figure, would not be sufficient to neutralize the 

 evident analogies. A more weighty ground for doubt is to be 

 found in the representation of the abdomen; nothing like its 

 remarkable breadth has been observed in any known Pyrgota; 

 moreover, it shows, instead of five segments, only four, the first 

 of which is abbreviated, and the second the longest; the ovi- 

 positor hardly exceeds one-third of the length of the abdomen, 

 while in the other Pyrgotse it equals the abdomen in length. If 

 these statements were based on Macquart's figure alone, I would 

 have been inclined to think that the abdomen, wanting in the 

 specimen, had been supplied by the imagination of the draughts- 

 man; but this supposition does not hold good in presence of the 

 fact, that Macquart mentions expressly, that he had a female 

 before him; and we know that the sex of a Pyrgota can only be 

 recognized by the structure of the abdomen. Macquart also says 

 that the ovipositor is flattened, which is not in the least the case 

 with P. millepunctata. These grounds seem sufficient to justify 

 the belief that Macquart's Oxycephala macvlipennia is a different 

 species from P. millepancto.ta,un\essv;e assume that Macquart's 

 specimen had the abdomen of a different species fastened to 

 it, Should this not be the case, there is every reason to doubt 

 ■whether the species is a Pyrgota at all. It is rather strange 

 that in the list of the exotic species described in Macquart's 



