CULICID^E OR MOSQUITOES 



557 



favourite resorts for the larvae of Anophelina are small natural collections of water, 

 such as puddles, ditches and small pools around swamps ; certain species (A. viaculi- 

 pennis, etc.) live in rain barrels as well. They may also occur in the sluggish water 

 at the edges of rivers or even in mid river, where the flow is checked by masses 

 of water weeds (Myzomyiafunesta, etc.). The Stegomyias prefer artificial collections 

 of water, but also occur in natural pools. The yellow fever species (S. fasciatd) 

 prefers small collections, such as in barrels, pots, jars, etc. Culex occur in all 

 manner of places rain barrels, tanks, cisterns, ponds and ditches. Some of the 

 South American species of Culex, Wyeomyia, Joblotia, etc., breed in the collections 

 of water at the base of bromelia leaves. 1 Very few Culicid larvae live in salt water 

 except in Australia, where Dr. Bancroft has found them in salt water of specific 

 gravity 1-040 (Mucidus alternans and Ctdex annulirostris). Other salt water 

 mosquitoes are known in America. The food of the larvae is very varied ; the 

 majority appear to feed upon confervae, small Crustacea and insects ; some are 



FIG. 395 . a, eggs of Culex ; <$' b*, eggs of Anopheles ; c, egg of Stegomyia ; 

 d, egg of Taeniorhynchus ; e, egg of Psorophora. 



cannibals, readily devouring others of their own kind. The larger larvae of Mega- 

 rhinus, Psorophora, Toxorhynchites and Mucidus are extremely ravenous and devour 

 one another. 



There are two main types of larvae, the Anopheline and Culicine ; in the former 

 there is no respiratory siphon, in the latter the siphon is long or moderately long. 

 The head offers certain marked peculiarities which are of specific value ; this 

 especially applies to the Anophelina, in which the frontal hairs are of great service 

 in distinguishing the larvae, 2 whilst in Culex the number and position of the spines 

 at the base of and on the siphon are characteristic. The position assumed by the 

 larvae in the water also varies in the different groups ; most of the Anophelines lie 

 horizontally, most of the Culicina and sEdeomyina hang head downwards. The 



1 " Wald Mosquitoes und Wald Malaria," Dr. Lutz, CentralbL f. Bakt., Par., u. 

 Infektionsk., i Abt. Orig., xxxiii, No. 4. 



2 Informaii n sent me by Dr. Grahham shows this statement to be not quite correct, as the 

 frontal hairs may vary in different stages of the same larva. This he has shown in Cellia 

 albipes, Theob., and I have noticed it in a Nyssorhynchus from Africa. 



