92 INSECTS AND MAN 



THREE DISEASES TRANSMITTED BY MOSQUITOES 



There is one family of insects, a large and cosmopolitan 

 family certainly whose members, collectively and individu- 

 ally, have probably done more than any other group in the 

 animal kingdom to impede man's progress in the universe, 

 have certainly brought upon man more illness and disease 

 than any other insects, and have actually " held up " some 

 of the greatest human undertakings. The mosquitoes, for 

 these are the obnoxious individuals, belong to the family 

 Culicidce which, it is almost unnecessary to state, is one 

 of the families of the order Diptera, or two-winged flies. 

 All the mosquitoes, with the exception of the members of 

 two genera, are provided with piercing mouths ; and every 

 female mosquito, with the exceptions mentioned, is probably 

 a sucker of blood ; certainly the majority imbibe this food, 

 whilst the males subsist on plant juices. Here, again, we 

 appear to be faced with an exception, for in Stegomyia the 

 yellow fever mosquito both males and females are said to 

 suck blood, but as a matter of fact only the females do so. 

 Let us consider, for the moment, what crimes must, of a 

 certainty, be attributed to the mosquitoes or gnats, the 

 names are synonymous, though this is not generally known. 

 As a matter of fact, every mosquito should be eyed with 

 suspicion, though, as yet, only a comparatively small 

 number of species are proved disease-carriers, but this 

 small percentage is responsible for the spread of such 

 terrible and widely distributed diseases as malaria, yellow 

 fever, and filariasis. 



Many parts of the tropics have been and are practically 

 uninhabitable by civilised man, owing to the ravages of 

 malaria, and this is especially the case in West Africa and 

 parts of India. Sir Patrick Manson, to whom medical 

 entomology owes so much, says that in the tropics " malaria 

 causes more deaths, and more predisposition to death, by 

 predisposing to other affections, than all the parasites affect- 



