170 STEGOMYIA FASCIATA [CH. 



In addition to its susceptibility to cold Stegomyia is even 

 more affected by dryness, especially when accompanied by 

 heat. The insect is somewhat protected from the vicissitudes 

 of the climate by its domestic habits, as it is generally found 

 inside houses. In fact its fondness for houses is so great 

 that, according to Boyce, it is never found breeding at distances 

 of more than 50 to 100 yards from buildings. 



On emerging from the pupa, the imago at once flies into 

 a house or other shelter, and generally settles down in some 

 dark corner and, like most other blood-sucking flies, it has a 

 great preference for dark-coloured objects. 



If the mosquitoes are breeding close to ships they often 

 enter them, and in consequence Stegomyia is the commonest 

 species found on board ship. In the old sailing ships, not 

 only could these insects live for weeks in the cabins, store- 

 rooms, holds, etc., but actually breed in the water that was 

 often left exposed in various receptacles. Although modern 

 steamers do not afford such facilities for the persistence of this 

 insect on board, yet recently there have been cases in which 

 live Stegomyia fasciata were found on ships that had been at 

 sea 13 to 20 days. 



Feeding habits. As in the majority of mosquitoes the female 

 Stegomyia is the only one which feeds on blood and this food 

 is necessary before the insect is able to lay its eggs. The male, 

 which is fully developed on emergence, does not bite, in spite 

 of statements to the contrary. It feeds on fruit juices and 

 also settles on the skin, to which it is attracted by the secre- 

 tions of the body. Although the male does not actually bite, 

 the singing noise produced by its wings is very annoying ; its 

 note is much higher than that of the female. 



The female does not feed on all persons indiscriminately, 

 but seems to exercise some choice in the selection of its victims. 

 Thus it prefers white people to black, in spite of its fondness 

 for dark objects. Similarly blondes are preferred to brunettes, 

 children to adults, and fresh arrivals from temperate regions 

 suffer more than acclimatized persons. The factors which guide 

 the insect in the selection of its host are not known, but scent 

 is probably the most important, after the effect of the body-heat. 



