102 DIPTERA OF NORTH AMERICA. [PART III. 



Kirby called this genus Seioptera. Following the usual rule 

 of latinization, I modified the name to Seoptera. Later, Rob. 

 Desvoidy called this genus Myodina; this name, however, cannot 

 supersede the older one of Kirby, which, moreover, characterizes 

 very well the peculiar habit of the species belonging here. 



1. S. colon Loew. % 9.— (Tab. IX, f. 6.) Nigra, nitida, fronte rufa, 

 antennis et facie ex rufo flavis, alarum macula apicali triangula et 

 cellulaB costalis basi nigris, stigmate subfusco. 



Shining black, front red, antennae and face reddish-yellow ; a triangular 

 spot on the apex of the wing and the basis of the costal cell black; 

 stigma brownish. Long. corp. 0.19—0.21 ; long. al. 0.19—0.22. 



Syn. Seoptera colon Loew, Berl. Eut. Zeitschr. XI, p. 296, Tab. II, f. 6. 



Of a shining black, somewhat bluish-black color; the abdomen 

 more glossy than shining. Front of a fiery red, opaque, along 

 the orbit of the eyes with a delicate line, powdered with white 

 pollen. Antennae yellowish-red ; the third, elongate-oval joint 

 is rather broad. Face and clypeus brilliant reddish-yellow, the 

 latter often, the former seldom, tinged with chestnut-brownish. 

 On the dorsum of the thorax there are two narrow lines of 

 whitish pollen, which extend beyond its middle ; they are easily 

 overlooked, although very distinct in well-preserved specimens. 

 Feet black, the tips of the femora and tibiae and the basis of the 

 hind tarsi have a reddish-brown tinge, even in specimens of the 

 darkest coloring ; in lighter specimens this coloring is brownish- 

 brickred, and extends not only over the greater part of the tibiae 

 and the hind tarsi, but is also perceptible at the root of the fore 

 tarsi. Halteres pale-yellowish. Wings hyaline ; costa, auxiliary 

 vein, and first longitudinal vein black; the other veins much paler, 

 generally yellowish when seen in a reflected light. The costal 

 cell blackened as far as the humeral crossvein ; the stigma, as 

 well as the whole subcostal cell, at the end of which it is placed, 

 brownish ; at the apex of the wing there is a triangular black 

 spot, which covers the extreme tip of the marginal cell as well as 

 the tip of the submarginal cell, and crosses a little beyond the 

 third longitudinal vein. The small crossvein is nearly under the 

 middle of the stigma, but beyond the middle of the discal cell ; 

 the last section of the fourth longitudinal vein is particularly long, 

 straight, gradually converging towards the third ; the anal cell is 



