Culicinae. 33 



in freshwater pools on the salt marshes. They never seem to- 

 breed in land or in purely fresh water swamps. 



The eggs are laid singly, white when first deposited, but 

 become black like G. dorsalis; they are spindle-shaped, rather 

 broadened at one end. As many as 200 may be laid by each 

 female. The eggs are laid on mud, both moist and dry, never, it 

 seems, in the water. The eggs remain dormant all the winter 

 and hatch out in the spring, when the water flows into the muddy 

 hollows where they were laid. This usually takes place in North 

 America about March, and the first brood mature about May. 

 The females from this brood lay eggs a few days after hatching in 

 the muddy depressions left by drying pools and tidal pools. They 

 can remain in this position three months. It appears that the eggs 

 must become dry or nearly so for three or four days before they 

 can hatch. The larvae are dirty grey to whitish, head yellow, 

 with or without diffused blotches ; respiratory siphon short, stout 

 and brown. The antennae are somewhat darkened apically, 

 taper gradually to a truncated apex with four spines. Halfway 

 up the antennae is a hair tuft of four longish hairs, and there are a 

 few scattered short spines ; the scales of the pecten are broad 

 basally, suddenly constricting to a fine point, with a row of seven 

 spines on each side ; the siphon has a row of spines on the lower 

 aspect of its basal half, the spines being long, thin and with one 

 or more teeth on one side. 



The larval life varies from seven to ten days. 



The pupal stage lasts from one to three days. The pupae are 

 provided with siphons having very oblique openings, the apices 

 being swollen and the broad anal plates with the central rachis 

 projecting well beyond their edges. 



Economic importance. This marsh mosquito is a very vicious 

 biter and causes much annoyance in the towns along the New 

 Jersey coast line and other littoral regions of North America. So 

 far it has not been shown to be connected with any mosquito-borne 

 disease. 



19. MANSONIA TITILLANS. Walker. 

 (The Riverside Mosquito). 



(Brit. Mus. List, p. 3, Walker; Dipt. Argentina, p.* 48, Arribalzaga 

 (Taeniorhynclms tacniorhynchus); Mono. Culicid. II., p. 175, 1901, 

 and III., p. 269, 1903.) 



General appearance. Head brown, with grey scales and 

 black, upright forked ones ; palpi yellowish, with dark scales and 



