304 Journal New York Entomological Society. t Vo1 - xxvii. 



the sides. Scutellum semi-oval, cushion-shaped, its posterior margin distinctly 

 though feebly swollen and separated from the disc by an impressed line. 

 Abdomen oval, its four basal segments together slightly longer than the 

 thorax ; first tergite very short, the second much the longest, the third and 

 fourth about of the same length (two thirds that of the second). Ovipositor 

 of the telescope-shaped type, composed of five segments which can be extended 

 to a considerable length or partially retracted within one another ; the basal 

 segment is much narrower than the fourth abdominal tergite, the following 

 segments are gradually narrowed, the apical one ending in two slender, straight 

 lamellae which are obtusely rounded at their tips. 



Wings long and narrow, over four times as long as wide, over twice the 

 length of the abdomen and slightly longer than the entire body (not includ- 

 ing the ovipositor) ; feebly smoky all over, brownish-yellow at the base and 

 in the costal and subcostal cells. Costa distinct along the entire hind margin 

 of the wing and reached by the diagonal vein. Only two submarginal cells 

 present, there being no cross-vein connecting the second and third longitudinal 

 veins. All the submarginal and first three posterior cells broadly open on the 

 costa. Anal cell broadly open. Alula well developed, broad. 



Measurements of the type: length not including the ovipositor (to apex 

 of tergite 4), 12.5 mm.; length of wing, 14.5 mm.; width of wing, 3.5 mm. 



In other females the length (not including the ovipositor) varies from 11 

 to 14 mm. 



Male. — Except for the usual sexual differences, very similar to the female. 

 The vertex is of the same width as in that sex. The markings of thorax and 

 abdomen are the same ; the sixth tergite is feebly gray pruinose at the base. 



Measurements of the allotype: length, 11 mm.; length of wing, 14.5 mm.; 

 width of wing, 3.5 mm. 



In other males the length varies between 12.5 and 14 mm. 



I have examined a number of specimens (15 $ and 9 J 1 ) and can 

 find but little difference between them, except in size and coloration 

 as mentioned above, and in certain details of the wing venation. 

 The peculiarities of the venation included in the above description 

 apply to all the specimens. In some of them, a short anterior cross- 

 vein connects the discoidal and the first submarginal cells, while in 

 others this vein is very much reduced or altogether absent. Also in 

 some the discoidal cell touches the fifth posterior cell, while in others 

 these two cells are separated by a distinct though short cross-vein. 

 These and some other minor discrepancies are combined in various 

 ways, as for instance in the specimen figured. 



In addition to the type and allotype, a number of topotypes of 

 both sexes have been examined and have been distributed among the 

 following collections: Entomological Department of Cornell Univer- 



