: OR MOSQUITOES, 417 



to trie tropics ; temperate regions suffer from them less than the two 

 extremes, but even there they form not only a source of great annoyance 

 but of danger, as malaria and possibly now and again yellow fever carriers. 

 A few years ago comparatively few species were known, now some 580 

 have been described. Their number will probably not stop far short of 1,000. 

 Some are purely domestic, others entirely sylvan ; the former, as we might 

 expect, often have a very wide distribution, having been taken from place 

 to place in boats and trains. The more rapid transport becomes, the greater 

 becomes the possibility of this wide distribution of many species increasing, 

 and the spread of other species from their natural home to foreign parts by 

 sea and then by trains further inland. 



All Culicidae 'are aquatic in their larval and pupal stages. Almost all 

 small collections of water, both natural and artificial, may form breeding 



FIG. 273. 



a, Eggs of Culex ; 6 1 b', Eggs of Anopheles; c, Egg of Stegomyia ; d, Egg of 

 Mansonia; ?, Egg of Psorophora. 



grounds for these pests. The 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. maculipennis, &c.) live in rain 

 barrels as well. They may also occur in the sluggish water at the edges o 

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

 weeds (Myzomyia funesta, &c.). The Stegomyias prefer artificial collec- 

 tions of water, but also occur in natural pools. The yellow fever specie 

 (5 fasciata) prefers small collections, such as in barrels, pots, jars, &c. 

 Culex occur in all manner of places-rain barrels, tanks, cisterns, ponds and 

 ditches Some of the South American species of Culex, Wyeomyia, Joblotia, 

 &c 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 



" Wald mosquitoes und Wald malaria," Dr. Lutz. Ccntnilbt. /. Bakt.. &*.. i. Abt. 

 Originate, Bd. xxxiii., No. 4. 



27 



