AEDES SANSONI 687 



mostly black ; tarsi black, each joint but the last of hind legs with a broad basal 

 ring of white scales, the first joint with some white scales scattered over the sur- 

 face; on the front and middle tarsi the bands are narrow, the last two joints of 

 the front tarsi and the last joint of the mid ones wholly black. Claw formula, 

 1.1-1.1-1.1. 



Length : Body about 5 mm. ; wing 4.5 mm. 



Male. Proboscis straight. Palpi exceeding the proboscis by about the length 

 of the last joint; end of long joint and the last two joints somewhat thickened 

 and bearing many long brown hairs ; long joint clothed with black scales, pale at 

 the middle, bases of last two joints with many white scales. Antennae plumose, 

 the last two joints long and slender, black, rugose, pilose, the others short, 

 largely pale, the hairs of the whorls long, dense, brown with yellowish-brown 

 luster. Coloration similar to the female. Wings much narrower than in the 

 female, the stems of the fork-cells longer ; vestiture sparse. Abdomen elongate, 

 depressed, the basal segmental bands broader, with dense, long, yellowish lateral 

 ciliation. Claw formula, 1.1-1.1-1.1. 



Length : Body about 5 mm. ; wing 4 mm. 



Genitalia : Side-pieces three times as long as wide, rounded at tip ; apical 

 lobe developed, running as a narrow ridge to the slight expanded basal lobe, 

 which is without a thick spine. Clasp-filament long, slender, uniform, with a 

 long articulated terminal spine. Harpes elliptical, concave, revolute on margin, 

 tip bent. Harpagones with a slender stem and long, slightly expanded terminal 

 filament, nearly as long as stem. Unci forming a basal cylinder. Basal lobes 

 slender, with long terminal spines. 



Larva, Stage IV (plate 118, fig. 408). Head rounded, widest through eyes; 

 antennse rather long, nearly uniform, spinulated, tuft rather small and before 

 middle ; upper pair of head-hairs double, lower pair single, ante-antennal tufts 

 in fours. Lateral comb of eighth segment of about twenty-five scales in a patch, 

 each scale with long central spine and fine lateral fringes. Air-tube about four 

 times as long as wide, tapering considerably on outer half ; pecten reaching to 

 middle, the last two teeth detached, followed by a long four-haired tuft. Anal 

 segment a little longer than wide, with a dorsal plate reaching well down the 

 sides ; dorsal tuft a long hair and tuft on each side ; lateral hair small, single ; 

 ventral brush well developed, with tufts preceding the barred area. Anal gills 

 longer than the segment, stout, tapering, equal. 



The larvje were obtained from eggs laid by a captured female, and their habits 

 in nature are unknown. It is, however, entirely probable that they are the same 

 as those of ahfitchii and related forms. The adults fly in the woods long after 

 the larvae have all disappeared, and bite readily by day. They do not frequent 

 houses. 



Mountains of western Canada and the north-western United States. 



Banff, Alberta (N. B. Sanson) ; Banff, Alberta, August 16 (E. P. Currie) ; 

 Kaslo, British Columbia, June 22, July 2, 1903 (H. G. Dyar) ; Juliaetta, Idaho, 

 April 21, 1899 (J. M. Aldrich) ; Eureka, California, May 22 to June 6, 1903 

 (H. S. Barber) ; Fieldbrook, California, May 26, 1903 (H. S. Barber). 



Dyar and Kjiab described sansoni from Alberta, from large specimens in 

 which there are no white scales on the wings nor on the last joint of the hind tarsi. 

 We have been inclined to hold as distinct certain specimens from California 

 which have a few white scales in the costal region of the wing and a very narrow 

 white ring on the last joint of the hind tarsi. We find, however, specimens from 

 the same locality marked like typical sansoni and others with only a minute patch 

 of white scales at base beneath, on the last hind tarsal. We are therefore con- 

 vinced that these all belong to one species. One female from Eureka, California, 

 has an abundance of white scales on the subcostal vein, but is not other- 



