534 MOSQUITOES OF NORTH AMERICA 



wards. Mental plate broad and short, with a central tooth and eight on each 

 side, all large and nearly equal. Mandible quadrangular, convex without, 

 smooth, a single appendage near tip; an outer row of few coarse filamentous 

 setae ; dentition of eight teeth, first and fifth long, especially the first, which is 

 projecting and sharp, the others diminishing successively; four oblique, tooth- 

 like projections below ; a small projection at angle ; a row of small setae near 

 base. Maxilla rounded rectangular, attachment oblique, the short palpus sessile 

 on outer angle ; various short spines and seta} on inner aspect. Palpus hardly 

 longer than broad, with four rudimentary digits. Thorax rounded, about as 

 long as wide, anterior margin strongly convex ; lateral single hairs long, tufts 

 short. Abdomen stout, the segments transverse, anterior ones strongly project- 

 ing laterally ; long lateral hairs double to fifth segment, single on sixth ; second- 

 ary hairs in small tufts. Tracheal tubes broad, band-shaped, nearly even. Air- 

 tube stout, conically tapered on outer half, tip very slightly Avidened, four times 

 as long as wide ; pecten reaching to middle of tube, long ; the single tooth a quad- 

 rangular scale with excavate base and roundedly furcate apex, one branch pro- 

 duced into a long hair; a single hair beyond middle of tube, beyond pecten. 

 Lateral comb of eighth segment a long curved row of scales preceded by a large 

 area of minute scales; single scale with a long thick terminal spine three 

 times as long as the scale, with a rounded process on one side and three on 

 the other. Anal segment longer than Avide, ringed by the plate ; dorsal tuft a long 

 hair and brush on each side ; a small lateral tuft ; ventral brush a series of short 

 tufts running the whole length of ventral line. Anal gills very long, three times 

 as long as the segment, regularly tapered to a sharp tip ; a wavy central trachea. 



Pupa (plate 149, fig. 704). Thoracic mass roundedly subpyriform; air- 

 tubes moderate, broadly funnel-shaped; abdomen very stout, central segTnents 

 with long terminal hairs ; a small tuft at apical angles of eighth segment ; anal 

 paddles large, broadly rounded, with minute terminal seta. 



Egg (plate 146, fig. 670). Broadly fusiform, covered with regular hexag- 

 onal reticulations, each with a stout recumbent spine attached to the end 

 towards the micropyle, half as long as the reticulation; a square gelatinous 

 cushion at the micropyle. 



The larvas are predaceous upon other mosquito larva, especially Psorophora 

 columhicB and Aedes sylvestris. They take no other food. The eggs are laid 

 singly on the ground, probably in the dry hollows where water usually collects 

 after rains. Apparently they do not hatch until the following season. They have 

 a spinose covering, exactly like that of the eggs of the P. columhicB on which they 

 usually feed. This probably preserves them from desiccation while the puddles 

 are dry. Immediately after a heavy shower, when the puddles are filled, the P. 

 cUiata eggs and those of their prey both hatch. The P. columbice grow with 

 surprising rapidity, and the P. ciliata, being initially larger, proceed to feed 

 upon them and grow with equal rapidity. It is essential that the development 

 should proceed as rapidly as possible, as these transient puddles often dry up 

 in a few days. Dupree and Morgan have detennined that adults develop in less 

 than five days. Indeed, the puddles often dry so soon as to preclude the develop- 

 ment of any adults of either the P. ciliata or their prey. A second rain, follow- 

 ing the first within a week, is usually essential to secure a successful brood. The 

 eggs do not all hatch at one time, but some of them hatch after every consider- 

 able rain. Provided there are enough of the prey, the P. ciliata pupate and 

 issue as adults promptly ; if by any chance their prey become entirely consumed, 

 the P. ciliata linger in the puddle imtil it dries or they perish of starvation. 

 Mr. Knab has observed that the larvae are fond of hiding beneath grass or other 

 floating vegetation. The winter is passed in the Qgg state. The females are 

 rather severe biters and, OAving to their large size, can puncture the skin of a 

 man through a considerable thickness of clothing. We haA'e no observations on 



