20 Guide to Insects and Ticks 



In a small case standing between the statue of Sir Eicharcl 

 Owen and the bust of Sir WiUiam Flower in Bay I is shown a 

 model of the yellow-fever mosquito, Steyuniijia fasciata, enlarged 

 28 diameters so as to be comparal)le with the enlarged models of 

 Cnlcx pipicns and Anoplteles macuUpciuiis shown elsewhere. On the 

 back of the panel is a map showing the distribution of the species. 



In general attitude a Stegomyia resembles a Cidex rather than 

 an Anopheles (fig. 2, p. 13) ; the thorax is arched, giving a hump- 

 backed appearance to the body. The thorax of Ste{iomi/ia fasciata 

 is black, with a conspicuous lyre-shaped wihte mark on the back ; 

 the tarsi are black, ringed with white at the base of each joint. 

 In Culex pipiens the thorax is brown, without distinct markings, 

 and the tarsi are black. 



Essentially a domestic species, Stegomyia fasciata is always 

 found in the vicinity of human habitations. Its wide distribution 

 is believed to be largely due to the insect, in the egg, larval and 

 adult stages, having been carried about the world in ships. It 

 breeds not only in water-barrels and cisterns, wells, and the bilges 

 of ships, but also frequently in puddles and pools of clean, foul, 

 or brackish water, and even in a small quantity of rain-water 

 standing in an old sardine-tin or broken bottle. The eggs are 

 remarkably resistant, and are not necessarily rendered incapable 

 of development if the water on which they are laid happens to 

 dry up. In one instance some eggs of Stegomyia that had been 

 kept in a dry state for six months gave rise to living larvae after 

 being placed in water. 



MOSQUITOES AND FILARIASIS. 



Pilariasis is a general term applied to diseases caused by thin 

 thread- worms of the genus Filaria. Elephantiasis, one of these 

 diseases, is due to Filaria bancrofti Cobbold, the embryos or larvae 

 of which are carried from man to man by certain mosquitoes, particu- 

 larly Ciilcx fatigans Wied. Mosquitoes are also responsible for the 

 spread of some other forms of filariasis, and it is interesting to note 

 that some species of mosquito spread both malaria and filariasis. 



In the table-case that stands at the entrance of Bay I are 

 shown the following mosquitoes known to be instrumental in the 

 spread of various forms of filariasis : — Anopheles maculipennis Mg. 

 (fig. 3, p. 15), A. {Myzorhynchus) sinensis Wied, var. nigerrimus 



