122 DIPTERA OF NORTH AMERICA. 



Pleurae with a narrow ferruginous longitudinal stripe on the supe- 

 rior border. Abdomen acorn-colored, with a darker middle stripe 

 interrupted at the incisions. Legs brownish-yellow, tibias usually 

 a little darker than the femora, tarsi blackened towards the tips. 

 Wings brownish-yellow, margined with blackish-brown on the 

 whole of the costal border, beginning from the base of the stigma 

 and ending a little beyond the tip of the fourth longitudinal vein ; 

 moreover, there are usually dark gray stripes between the longitu- 

 dinal veins ; the transverse veins are margined with dark brownish- 

 black ; the small transverse vein is placed a little before the middle 

 of the discal cell ; the posterior transverse vein is very arcuated in 

 the shape of an S, and has a very oblique position ; in most spe- 

 cimens the fourth longitudinal vein has some small stumps, most 

 of which are emitted from its inner side, each being inclosed in a 

 dot-like brownish black cloud. Such specimens resemble very 

 much the European Tet. aratoria Fabr. 



Hob. Sitka. Middle States. (Osten-Sacken.) 

 Observation. The name of Tet. vicina is preoccupied by R. 

 Desvoidy. 



13. T. trianglllaris LOEW. J. (Translated from Berlin. Entom. 

 Zeitsch. 1861, p. 344, by B. Osten-Sacken.) Glandicolor, thorace bili- 

 neato, frontis opacse vittulis lateralibus Isevigatis, subobsoletis, fossula 

 media distincta, nou dilatata, subtriangula, antenuarum seta pilis longis, 

 rarioribus, nigris plumata, alis lutescentibus, unicoloribus, venis trans- 

 versis fusco-limbatis, posteriore subrecta. 



Acorn-colored, thorax with two lines, front opaque, its lateral stripes 

 shining, almost obsolete, the furrow in the middle distinct, not dilated, 

 subtriangular, anteunal bristle with long, rare, black hairs, wings lutes- 

 cent, unicolorous, transverse veins margined with fuscous, the posterior 

 one almost straight. Long. corp. 0.26 0.27. Long. al. 0.27. 



Occiput yellow, with a large shining-white spot. Front bright 

 yellow, entirely opaque, the ordinary lateral stripes shining, narrow, 

 almost obsolete ; the furrow in the middle distinct, shining, not 

 dilated, very shortened, subtriangular. Antennas rather short, 

 ochraceous, last joint a little longer than the two preceding taken 

 together, ferruginous at the tip, bristle with long but rather rare, 

 black hairs. Face shining-white, immaculate. Thorax above 

 with two darker, very approximated, lines. Abdomen unicolored. 



