CULISETA IMPATIENS 487 



specially prominent; two stout and two slender filaments before collar; a row of 

 cilia outwardly; twenty filaments on outer margin in a double row, the outer 

 ones short, all bluntly tipped; dentition of five teeth on a process, the second one 

 the longest, two rounded teeth before, three at base, a broad serrate filament 

 within; process below short, rather widely furcate, with hairs outwardly; basal 

 angle blunt, a group of hairs within ; a row of long hairs at base. Maxilla 

 hemispherical, divided by a suture which runs inwardly, the inner part being 

 parallel to base; inner half hairy toward margin, with a group of small hairs 

 near angle of suture ; two hair-tufts at tip ; outer half sparsely haired without, 

 two stout separate filaments situated near suture subapically. Palpus small, with 

 four curved apical digits. Thorax rounded, wider than long, robust; hairs 

 abundant, single hairs rather long, prothoracic tufts multiple and nearly as long 

 as head. Abdomen stout, the anterior segments short; hairs rather short, lateral 

 hairs multiple to fifth segment, double on sixth, single on seventh, confused by 

 subdorsal and subventral tufts, which are rather long on third to sixth segments. 

 Tracheal tubes moderate, not band-shaped, flexuous posteriorly. Air-tube stout, 

 tapered outwardly, two and a half times as long as wide; pecten of small teeth 

 at base, becoming long hairs beyond basal fourth and running to apical third ; 

 single spine with three basal branches, except in the case of the outer hair-liko 

 spines; a large tuft close to base, almost at base of pecten. Lateral comb of 

 eighth segment of many scales in a triangular patch; single scale with apical 

 part long and widened a little outwardly, evenly fringed with long spinules. 

 Anal segment about as long as broad, ringed by the plate ; dorsal tuft a group of 

 three hairs and brush on each side ; a two-haired lateral tuft ; ventral brush well 

 developed, with small tufts preceding nearly to base. Anal gills small, shorter 

 than the segment, their tips rounded. 



The eggs are laid in large boat-shaped masses, floating on the water, and hatch 

 within a few days after being laid. The growth of the larvae is slow. The pupal 

 state lasts but a few days. The adult females go into hibernation, to emerge 

 early in spring and deposit their eggs. The larvae are inhabitants of permanent 

 water, cold spring-holes or holes left by overturned trees being natural breeding- 

 places. They do not take to artificial breeding-places, such as water barrels, and 

 seem confined to their original wild habitat. The species is consequently rare, 

 except perhaps in the far North. The larvae inhabit clear, cold water. A favo- 

 rite locality, kindly shown to one of us by Dr. Felt, is a large pool at the foot of 

 a cliff near the summit of Cobble Hill, at Elizabethtovni, New York, which is 

 fed by the melting of ice in some ice caves. This pool is very large early in 

 spring and is then filled with larvte of other species ; the impatiens larvas appear 

 later from eggs laid by the hibernated females. The adults are not troublesome. 

 Besides being rare, only approaching by individuals, they are deliberate in their 

 attacks and easily alarmed. They are also slow to bite, though their large size 

 may easily cause apprehension in a prospective victim. We have not observed 

 the adults in houses. They frequent the woods near their breeding-places. The 

 mating habits have not come under observation, and no mating swarms have 

 been seen. 



North America, throughout the northern part of the continent from ocean 

 to ocean, in subboreal situations. 



Weld, Maine, August, 1910 (H. G. Dyar) ; Monadnock, New Hamhshire, 

 May 1, 1911 (A. H. Thayer) ; Cobble Hill, Elizabethtown, New York, April 25, 

 August 8, 1905 (H. G. Dyar) ; Tupper Lake, New York (H. G. Dyar) ; Water- 

 ville. New Hampshire (A. D. Hopkins) ; White Mountains, New Hampshire 

 (H. K. Morrison) ; Kaslo, British Columbia (H. G. Dyar) ; Sitka, Alaska, 

 June 16, 1899 (Harriman Expedition, T. Kincaid, collector) ; Yakutat, Alaska, 



