ORTALID^E PYRGOTA. 79 



beyond the end of the anal cell, there is a small, almost hyaline 

 spot; the alula is almost hyaline, or infuscated towards the^ 

 posterior margin only. The second longitudinal vein, opposite 

 the posterior crossvein, shows a small fold, the tip of which, 

 directed backwards, emits a short stump of a vein; the last 

 section of the fourth longitudinal vein is very strongly curved ; 

 the posterior angle of the anal cell forms a sharp, but not very 

 acute angle. 



Hob. United States; Carolina (Zimmerman), Massachusetts 

 (Harris), etc. 



Observation. I am not able to compare the figure of Myopa 

 nigripennis Gray, but I do not hesitate, on Gerstsecker's authority, 

 to place this name among the synonyms of P. undata. The 

 synonymy of Sphecomyia undata Harris is based upon a state- 

 ment of Mr. Walker, who seems to have received specimens from 

 the author. 



3. p. vespertilio GERST. $ . Antennarum articulo tertio prsece- 

 dente plus dimidio breviore, rotundato ovato, fusco, aristae articulo primo 

 brevissimo, secundo elongate : fronte oculis duplo latiore, palpis filifor- 

 mibus : alis vena longitudinal! secunda nee fracta, nee appendiculata, 

 alula strigisque duabus marginis posterioris hyalinis. 



Third antennal joint not half so long as the second, rounded oval, brown ; 

 the first joint of the arista very short, the second elongated; front 

 double the breadth of the eyes ; palpi linear; second longitudinal vein 

 of the wings without fold or stump of a vein ; the alula and two stripes 

 near the posterior margin hyaline. Long. corp. 0.64; long. al. 0.56. 



SYN. Pyrgota vespertilio GERST. Stett. Entom. Zeitschr. xxi, p. 189, Tab. II, 

 f. 8. 



Head comparatively stouter than in the preceding species ; 

 front, when viewed from above, and taken as far as the anterior 

 border of the eyes, at least by one-half broader than long ; the 

 gibbosity projecting over the eyes is not of equal breadth, as in 

 P. undata, but conically attenuated anteriorly; its tip is as 

 broadly truncated as in the other species ; viewed in profile, this 

 projection is as high as in P. undata; its anterior side, however, 

 does not ascend in a straight line, but shows a strong convexity, 

 so that the tip itself is retreating. The cheeks are consider- 

 ably broader and more sunken. The eyes are comparatively 

 smaller, the excavated upper part of the face perceptibly shorter. 

 The coloring on the front, especially on the inside of the eyes and 



