REPORT ON ^lOSOUITOES. 177 



Description of the Larva. 



The larva and details are illustrated on figs. 51 and 52. The 

 full-grown wriggler averages 10 to 12 mm. ,=.40 to .44 of an 

 inch in length, though specimens occasionally attain the immense 

 length of 15 mm. ,^.60 of an inch exclusive of the anal siphon. 

 They are usually pale gray in color but sometimes dark gray. 

 The head is quadrate, widest at the eyes, slightly excavated on 

 the anterior margin, pale brown in color, and more or less 

 blotched with dark brown spots, though often uniformly colored. 

 Two small hair tufts of four or five hairs are on the vertex, 

 near the anterior margin. The antenna (fig. 52, 10) is yel- 

 lowish, moderately long and slender, but thick near the base; 

 the extreme apex has two short spines and a small joint, and on 

 a slight offset near the apex are two other spines, one very long 

 and one short. A few large, stout spines are on the basal half, 

 and a slender one, representing the tuft, issues from the shaft 

 one-fourth the length of the antenna from the apex. The eyes 

 are small and occupy the part where the head is widest. The 

 mouth brushes (fig. 51, 21) are small, brown in color and close 

 tightly at the sides of the head when not in use. They are com- 

 posed of stout hairs, comb-toothed at the apical half, and figure 

 51, 3, shows one of these hairs greatly enlarged. The mentum 

 (fig. 52, 7) is short and very broad, with seven to nine teeth on 

 each side of the apex; the apical tooth large, as are the two next 

 to the basal, the terminal and basal teeth smaller and uniform. 

 The mandible (fig. 51, 4) is triangular in form, the longest side, 

 rounded; the teeth very large and there is but a single dorsal 

 •spine. The maxillary palpus (fig. 51, 4) is chunky, the surface 

 covered with short hairs and spines, the apex with short, thick 

 spines, the basal joint small and somewhat retracted. The epi- 

 pharynx and hypopharynx are shown from above and below at 

 figures 52, 2, 6, 8 and 9. 



The thorax is almost as long as broad, not angular, and with 

 three groups of short hair tufts issuing from each lateral margin. 



The abdominal segments from one to seven are very stout and 

 robust, with short tufts of hair set in small depressions at the 

 sides, each tuft of from three to five hairs, the larger number in 

 the anterior segments. The eighth segment has the lateral 

 patches of scales (figure 51, 5) consisting each of a large patch 

 of minute scales edged at the anterior margin with a single row 

 of from ten to sixteen large scales, the individual scale with a 

 long, stout apical spine and one or two smaller ones at the sides. 

 12 MO 



