92 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



Coxae black with yellow tips and white hairs; anterior paii with 

 silvery pollen on the front surface, which is j^ellow nearly up to its 

 middle. Femora black with green or blue reflections; middle pair 

 with a few white hairs below; hind pair ciliate on lower inner edge 

 with long white haus, those toward the apex as long or longer than 

 the width of the femora, those near the base shorter; middle and hind 

 femora each with one preapical bristle. Tibiae yellow; posterior pair 

 enlarged at tip and blackened from near their middle, the glabrous 

 stripe abo/e narrow and reaching from the base to beyond the middle. 

 All femora and fore and middle tibiae and tarsi with white or silvery 

 pollen on their anterior surface. Fore and middle tarsi a little longer 

 than their tibiae and wholly yellow, except the extreme tips of all the 

 joints which are blackish. Hind tarsi (fig. 50a) deep black, but 

 appearing yellowish in certain lights, this yellow color being caused 

 by minute yellow hairs; first joint with a few rather small bristles 

 above, first and second joints of nearly equal length, the third, fourth, 

 and fifth joints each about three-fourths as long as the preceding, 

 slightly compressed and fringed above with long black hairs. Calyp- 

 ters and hal teres yellow, the former with white cilia. 



Wings (fig. 50) grayish with the costal edge brown as far as the 

 tliird vein, fourth and fifth veins and the cross-vein margined with 

 broMTUsh; costa scarcely enlarged at tip of fiist vein; last section of 

 fourth vein bent before its middle; hand margin of wing slightly in- 

 dented at tip of fifth vein; anal angle rounded, not very prominent. 



Female. — Face broad, white or silvery; hind tibiae yellow, black on 

 apical third; hind tarsi plain, wholly black; all femora and fore and 

 middle tibiae and tarsi with about the same silvery pollen on their 

 front surface as is found in the male; fore and middle tarsi yellow with 

 the tips of all their joints black; middle tibiae wdth one bristle below, 

 their basitarsi without a bristle above; brown on the wings paler than 

 in the male, and the anal angle more prominent; costa without an 

 enlargement at tip of first vein. 



Redescribed from 4 males and 3 females. One male was taken at 

 Olympia, Washington, June 22, 1895, by Trevor Kincaid (now in the 

 Aldrich coll.); 2 males and 1 female taken at Bar Harbor, Maine, 

 July 26, 1919, on water-lil}^ pads, by C. W. Johnson; 1 pair taken at 

 Cranmore, Wisconsin, July 12, 1909, by C. W. Hookei ; I took a 

 female at Toronto, Ontario, July 12, 1918. 



This species seems to be found on plants that float on the water, 

 such as water lilies; they are never or seldom found on erect plants, 

 either growing in the water or along the sides of the ponds. 



Location of type unknown; presumed to be in Stockholm. It was 

 described from northern Europe. 



