296 MOSQtriTOES of NOKTH AMERICA 



rods, two serrated setae, and three pointed setae. Clasp-filament large, slender, 

 with an articulated terminal claw. Harpes stout, columnar, with serrated tips. 

 Harpagones columnar, exceeding the harpes in length, with an inner slender 

 branch projecting at right angles, apex tapered, bearing a row of hairs. Basal 

 appendages short, approximate, setose. 



Larva, Stage IV (see figure of the entir»4arva, plate 50). — Head large, sub- 

 quadrate, broad, wider than long, sides ^raight, a broad notch at insertion of 

 antenna, front margin broadly arcuate*^ Eyes large. Antennae long, basal two- 

 thirds thickened, finely spined, a large tuft at outer third, part beyond slender; 

 two very long hairs before the tip, a long hair, a short one, and a digit at apex. 

 Both pairs of dorsal head-hairs single, ante-antennal tuft multiple. Mental 

 plate quadrate, the sides oblique ; apical tooth large, five equal teeth on each side, 

 followed by two very small ones on sides. Mandible quadrangular, elongate, 

 two filaments before the tip, with four small hairs arising from their bases; an 

 outer row of cilia from a collar ; a few very small hairs on outer margin ; denti- 

 tion of four teeth on a process, the first very large ; a long spine-shaped tooth 

 before, an irregular group of three at base, a very long serrate filament and row 

 of feathered hairs within ; process below rounded, with a slight notch on inner 

 side and a few scattered hairs; angle below sharp and narrow; four long 

 scattered hairs within and a row at base. Maxilla elongate, narrow, divided by a 

 suture; inner half with coarse hairs inwardly, with some fine hair near the 

 suture; a row of long hairs at apex running along the suture; outer half with 

 some fine hairs next the suture ; filaments small and basally placed ; spine on 

 other side near apex, long. Palpus small, rather slender, with five slender apical 

 digits. Thorax rounded, wider than long; hairs abundant, very long, anterior 

 thoracic ones nearly twice the length of the head. Anterior abdominal segments 

 short, posterior ones elongated; lateral tufts of the first two segments multiple, 

 those of third to sixth double; secondary hairs rather well developed; tracheal 

 tubes narrow, linear, somewhat separated in the seventh segment. Air-tube 

 long, somewhat conical on basal third, tapered, but expanding again at apex, 

 about seven times as long as wide; pecten on basal third, of evenly spaced teeth; 

 separate teeth slender, with" two basal branches; four small tufts along posterior 

 margin beyond pecten. Lateral comb of eighth segment a patch of scales 

 several rows deep; single scale with expanded apex, finely fringed all around. 

 Anal segment nearly twice as long as broad, ringed by the plate; a dorsal hair 

 and sparse but long tuft on either side, a single lateral hair; ventral brush 

 moderate, confined by the plate. Anal gUls longer than the segment, with 

 rounded ends. 



Pupa (plate 148, fig. 698). — Thoracic mass subpyriform; small tufts on the 

 head and prothorax; air-tubes long, slender, scarcely expanded; abdomen stout, 

 the lateral hairs very slight, only forming a sparse tuft on the eighth segment. 



Eggs (plate 147, fig. 688) .— Subcylindrical, slightly tapered toward upper 

 end, black, arranged upright in the form of a raft, in the manner lypical of 

 Gulex. 



The larvae frequent especially marshes and edges of ponds, where protected by 

 vegetation. The females hibernate. The larvae appear at first in small numbers, 

 but late in the season become abundant in all stagnant or vegetation-filled 

 water throughout temperate North America. The adults apparently do not bite 

 man, and nothing is known of their habits. Mr. Knab has published the follow- 

 ing observations on the egg-laying habits : 



"During the summer of 1903, in examining rain-barrels for mosquito 

 material, egg-clusters were several times found upon the sides of the barrel some 

 distance above the surface of the water. At first it was thought that these egg- 

 boats had come into that situation by some disturbance of the water, but later 

 a number of them were found in the same barrel and at different heights from 



