238 NORTH AMERICAN TRYPETINA. 



Observation. — Trypeta canadensis resembles the species of 

 Acidia in its general habitus and, at first sight, seems to differ 

 only in the somewhat modified picture of the wings, which seems 

 to hold the middle between the rivulet and the crossband. A 

 closer examination shows, that in the structure of the head and 

 of its parts, as also in the bristles upon the feet, this species is 

 closely allied to Acidia, but that it also shows characters not 

 belonging to that genus ; such is the structure of the ovipositor, 

 which is longer, quite flattened, and broadly truncate at the end; 

 also the very peculiar course of the section of the fourth longitu- 

 dinal vein preceding the small crossvein. If the scutellum is 

 provided with six bristles in normal specimens, we would, have 

 another important distinctive character from Acidia. Thus the 

 admission of T. canadensis in the genus Acidia would render the 

 limitation of this genus too indefinite, and it becomes necessary 

 to establish a new genus for it, which would be characterized by 

 a modified type of the picture, a peculiar course of the fourth 

 vein, and a different structure of the ovipositor. I will call this 

 genus Epochra. 



11. T. longipennis Wied. % 9. (Tab. X, f. 2 £, 3 9 .)— Lutea. 

 capite tumido, corpore elongato et angusto ; alse longse et angustae, 

 maris adhuc longiores et angustiores quam feminae, rivulis luteo-fuscanis 

 pictae. 



Clay-yellow ; head tumid ; body long and narrow ; wings long and nar- 

 row, those of the male still longer and more narrow than in the female, 

 pictured with yellowish-brown rivulets. Long. corp. 0.17 — 0.26; long. 

 al. 0.22—0.30. 



Syn. Trypeta longipennis Wiedemann, Auss. Zweifl., II, 483, 12 (£ 9 ). 

 Strauzia armata R. Desvoidy, Myod. 719, 2 (£). 

 Strauzia inermis R. Desvoidy, Myod. 718, 1(9)- 

 Te.phritis trimaculata Macqoart, Dipt. Exot., II, 3, p. 226, 8. Tab. 



XXXI, f. 3. 

 Trypeta cornigera Walker, List Brit. Mus., IV, p. 1010. 

 Trypeta cornifera Walker, List Brit. Mus., IV, p. 1011. 

 Trypeta longipennis Loew, Monographs, etc., I, p. 65. 



It cannot be doubted that Trypeta longipennis Wied., either 

 is a very variable species, or that North America possesses a 

 number of closely allied species, resembling it very much, and 

 which, as long as they are represented only by single, often 

 imperfectly preserved specimens, it is as difficult to distinguish 



