740 MOSQUITOES OF NOKTH AMERICA 



from a collar; fourteen filaments on outer edge; dentition of three teeth, first 

 and third longer, the usual fourth rudimentary ; a process before, three teeth at 

 base, a broad serrate filament and six serrate hairs within ; process below cleft- 

 furcate, with hairs at tip, a row of hairs at base ; a sharp basal angle ; six hairs 

 in two groups within; a row of stout hairs at base. Maxilla elongate hemi- 

 spherical, divided by a suture ; inner half hairy, a row of hairs up the sides and 

 a series of short erect ones on the edge, a tuft of long, stout hairs at tip ; outer 

 half with some hair, two long filaments near the suture, and a spine on the other 

 side; palpus oblique, with four small digits, the inner two smallest. Thorax 

 rounded, a little wider than long; hair abundant, some of the single lateral 

 ones long. Abdomen moderate, the anterior segments shorter; hairs slight, the 

 lateral ones of first two segments double, the rest single ; tracheal tubes broad, 

 band-shaped, slightly expanded in the segments. Air-tube stout, tapered be- 

 yond base, about three times as long as wide ; pecten not reaching to middle, of 

 uniformJy spaced teeth, followed by a single tuft of about eight hairs; single 

 spine long, with wide base and one to three basal branches. Lateral comb of 

 eighth segment of many scales in a triangular patch; single scale elongate, 

 fringed with coarse spinules, the apical one distinctly the longest. Anal seg- 

 ment longer than wide, dorsal plate reaching two-thirds of the way down the 

 sides, sinuate on lateral margin; dorsal tuft a brush and hair on each side; a 

 single lateral hair ; ventral brush well developed, with a few short tufts preceding 

 barred area ; anal gills long, ensif orm, twice as long as the segment. 



Larva, Stage I. — Head elliptical, rounded; mouth-brushes well-developed; 

 eyes small, elongate elliptical. Thorax roimded, enlarged; abdomen sub- 

 monilif orm, hairs moderately long, single, the lateral ones double on segments 

 1 to 4, gradually becoming shorter and weaker posteriorly. Lateral comb 

 of eighth segment a single row of short, stout, pointed-tipped spines. Air-tube 

 three times as long as wide, conical at tip, with short, simple basal pecten and 

 hair beyond. Anal segment with dorsal tuft paired, two hairs in each half ; no 

 ventral brush ; four anal processes longer than the segment. 



The larvae develop in the early spring in pools from melting snow, hatching 

 from overwintering eggs. There is but a single annual brood, tiie females living 

 two or three months and inhabiting forests. They are practically all gone at 

 lower altitudes by August, but in higher altitudes or cool places may be found 

 later. Dr. Dyar says: 



" Early pools in the mountains, filled by the drainage from the melting snow 

 banlcs, contained the larvge and pupae, apparently by the million. Near Kootenay 

 Lake they had all gone in May; but higher in the hills larvae could still be found 

 till the middle of June, and at Kokanee Mountain, at the foot of the glacier, I . 

 found many larvae on August 10. The adults soon became very common in the 

 woods, though in a few weeks they were much worn and later disappeared, except 

 in the high damp valleys where they persisted longer. Eggs were obtained of 

 the usual spindle shape but shorter and thicker than those of C. cantans 

 [=Aedes sansoni]. They were laid singly and hibernated." 



Northern Eocky Mountain region. 



Kaslo, British Columbia, June to August, 1903 (H. G. Dyar) ; Juliaetta, 

 Idaho, April 21, 1899 (J. M. Aldrich) ; Summit, Placer County, California, 

 July 19, 1915 (H. G. Dyar). 



This species has undoubtedly a wider distribution than indicated by our 

 localities. Our collections, however, are useless in this group unless they contain 

 males or larvas, which is rarely the case. As in other species, there is indication 

 of variation in the coloration of the adults. This is particularly true of the dark 

 stripes of the mesonotum, which show a tendency to become obsolete. 



