MOSQUITO BIOLOGY 63 



half times as long as broad. Prior to last larval stage head larger than 

 thorax, usually immaculate ; in last stage, smaller than thorax, more 

 chitinized, with blotches on vertex variously shaped and diffused, but 

 always bisymmetrical. Near anterior part of head four tufts, each 

 composed of four or five hairs, somewhat larger tuft at base of each 

 antenna. Antennae large, long, thickest near base, tapering slightly for 

 two-thirds length, abruptly very narrow to apex, leaving offset upon 

 which large tuft of long hairs extending considerably beyond tip. Apex 

 with three long bristles, a short one, and a small articulated joint. 

 White, except apical third and base; black surface covered with fine 

 hair-like spines. Eyes large, black and occupy broadest part of head. 

 Rotary mouth brushes entirely composed of simple hairs. Mentum 

 pentagonal, with fifteen to twenty-one teeth, always with equal number 

 on each side of apical tooth. Mandible triangular with blunt corners. 

 Maxillary palpus has rather small tuft at apex; surface clothed with 

 patches of hair and basal joint very small. Thorax wider than long, 

 angles very acute in small and half grown larvae. Beside normal lateral 

 hairs, four small tufts of two or three long hairs each, extending for- 

 ward over head on anterior margin, and several smaller tufts between 

 these and first lateral tuft. 



Abdomnial segments from one to six subquadrate, deeply constricted 

 at joints, especially in anterior segments. Two hairs in lateral tuft in 

 all except first and second segments, these with three or four hairs ; 

 smaller very fine tuft hairs also on dorsal part of segments near lateral 

 borders. Seventh segment has only short hair tufts. Scales of lateral 

 patches on eighth segment small, from twenty-eight to fifty in each 

 patch irregularly arranged. Single scale has long fringes at sides and 

 apex. Anal siphon long, slender, not concave, evenly tapered, varying in 

 length from five to seven times its width at base. From twelve to eighteen 

 spines in each lateral row, extending about one-third from base, indi- 

 vidual spines broad and light colored, with three or four teeth each; 

 small short tuft terminates each row, several smaller ones toward apex. 

 Ninth segment slightly longer than broad, with hairs in ventral row of 

 tufts rather short, double dorsal tuft mostly with very long hairs. 



HABITS OF THE EARLY STAGES 



Egg boats of this species seem to disintegrate rapidly and are rarely 

 found. The larvae occur everywhere on the marsh in salt as well as fresh 

 water, but as a rule they are more abundant along the edges of the 

 highland than nearer the shore. No specimens have been collected prior 

 to the last days of May, though as they were then two-thirds grown, it 



