REPORT OX MOSQUITOES. 211 



head, rarely, does occur and is due to the extension of this ante- 

 rior blotch. Four rather long, single hairs arise from the sides 

 of the vertex in the anterior part, two slightly in advance of 

 the others, and a small tuft of four or five hairs is at the base 

 of each antenna. The antenna is short (fig. 61, 6) and evenly 

 tapered toward the apex ; pale yellow at the base, dark brown on 

 the apical half and with small stout spines over the surface. The 

 tuft of four or five hairs issues from the shaft at about the middle, 

 and the apex has a few short bristles besides the small joint. The 

 eyes are large, some being blunt and others acute on the dorsal 

 surface. The rotary mouth brushes (fig. 61, 2) have the more 

 central hairs pectinated. The mentum (fig. 61, 3) is triangular, 

 with eight to twelve teeth on each side of the apex. The mandi- 

 ble (fig. 61, 4) is normal but somewhat elongated, and the 

 maxillary palpus (fig. 61, 5) is short and chunky with a hairy 

 surface, a large basal joint and comparatively a verv- small apical 

 tuft. 



The thorax is large, wider than long, with two transverse 

 depressions on the dorsal surface and a number of smaller 

 wrinkles. The angulations are not very prominent and the hair 

 tufts arising from them very short; there are two other small 

 tufts on the dorsum near the anterior margin. 



The abdominal segments are subquadrate in form, the joints 

 more constricted in the anterior segments. The hair tufts are 

 ver}^ short, two hairs to the lateral tuft, but more in the first, 

 second and seventh segments. The eighth segment has lateral 

 patches of scales from twenty to forty in number, the single scale 

 (fig. 61, 8) drawn to an acute point at the apex and with small 

 spines fringing the sides. The anal siphon (fig. 61, 7) is short 

 and stubby, about one and one-half or twice as long as broad, 

 with two rows of toothed spines from sixteen to twenty-four 

 in each. The spines have from one to five teeth and may be either 

 slender or stout, as shown in the figures. The ninth segment is 

 small, almost square and completely ringed by the chitinized 

 saddle. The dorsal tufts are normal, while the ventral brush is 

 thick, composed of short hairs, the tufts confined to the barred 

 area. The anal gills are very short, often no longer than wide. 



Habits of the Early Stages. 



When the eggs become covered with water by rains or by the 

 tides the larvse develop and emerge, often within a period of 

 minutes rather than hours. They thrive equally well in salt or in 

 fresh water and develop most rapidly where the food supply is 



