ORTALID^E — EUXESTA. 153 



broad and has a sharp posterior angle, although it is hardly 

 drawn out in a point. 



Eab. New York (Osten-Sacken) ; Illinois (Kennicott). 



Observation 1. — This species, as far as I know, is undescribed, 

 although not absolutely new, because Wiedemann, as his collec- 

 tion shows, received it from Say under the name of Ortalis colon. 

 Harris, in his Catalogue of the Insects of Massachusetts, also has 

 0. colon, which is undoubtedly the same species. I preserved 

 the name which Say gave it, although I do not find it described 

 in his works. 



Observation 2. — Seoptera colon is so exceedingly like the 

 European S. vibrans Lin., that as long as I had only indifferently 

 preserved specimens of it, I took it for the latter species. 

 Although the differences are only slight, they are so constant that 

 the specific distinctness of the two species cannot be called in 

 doubt. The front of S. colon is somewhat broader than that of 

 S. vibrans; the two whitish stripes of the thorax in S. colon, 

 although but little apparent, can easily be traced beyond the 

 middle of the dorsum, while in S. vibrans it is not without 

 difficulty that their anterior end alone can be perceived. The 

 abdomen of S. colon is always less shining, and its blackish color 

 more bluish, while S. vibrans has it more blackish-green. The 

 costal cell of 8. colon is blackish as far and even a little beyond 

 the humeral crossvein ; in S. vibrans this cell is entirely hyaline 

 as far as its extreme basis ; the stigma of S. colon is brownish, 

 that of S. vibrans black or brownish-black ; finally the black spot 

 at the tip of the wings is somewhat different in both species ; that 

 portion of it which crosses the third longitudinal vein is of more 

 equal breadth in S. colon, whereas it becomes more narrow 

 towards the margin of the wing in S. vibrans. 



Gen. VII. EUXESTA Loew. 



Char act. — Front of equal, medium breadth, even, rather coarsely hairy. 

 Antenna, short, the third joint almost round or rounded-oval, with a 



thin, bare arista. 

 Face more or less excavated, clypeus projecting. 

 Thorax with bristles on the hind part only ; scutellum convex. 

 Wings: posterior angle of the anal cell drawn out in a point ; the 



last section of the fourth longitudinal vein converges towards the 



third ; posterior crossvein perpendicular. 



