132 B.C. Entomolocucal Societ.y. 



THE IMPORTANCE OF MOSQUITOES, WITH NOTES ON 

 SOME BRITISH COLUMBIA SPECIES. 



By E. Hearle. 



Mosquitoes are responsible for half the entire mortality of the human 

 race. This is due to their position as the transmittens of malaria alone, 

 according to Dr. Creighton, the noted authority on that disease. The 

 mosquitoes of the tropics " have their spears poisoned with death-dealing 

 disease-germs " and do not fight a clean warfare as do their northern 

 relations. They and their accomplices have played a great part in moulding 

 the destiny of the world. The fertile plains of Africa might have been the 

 centre of the world's civilization; but, instead, the deadly swarms of 

 mosquitoes and the malaria carried by them have shut off Africa more 

 effectively than the greatest natural barriers could have done. When one 

 realizes the terrible proportions as.sumed by malaria, yellow fever, dengue, 

 and filariasis in many parts of the tropical world, and that these diseases 

 are transmitted solely by mosquitoes, it is evident that Dr. Creighton's 

 statement is by no means extravagant. India alone lost 5,000,000 people 

 in one year from malaria. 



In temperate and northern countries mosquitoes exert a very important 

 economic influence in many districts. They do not, it is true, invoke the aid 

 of that dread ally, disease ; but their own spears are weapons enough with 

 which to wage a terrible warfare. In some areas the bloodthirsty hordes 

 occur in such enormous numbers that progress and development are retarded 

 and life is made intolerable for man and beast. Much of New Jersey was 

 thus eft'ected, and in the 1917 Report of the Department of Conservation 

 and Development the Board states that it " is convinced that the salt-marsli 

 mosquitoes, more than anything or than all else, are responsible for the 

 backwardness of the eastern and southern sections of the State. They have 

 depopulated farms, prevented the growth of towns, hampered the 

 development of shore resorts, and restricted the extension of suburban 

 communities." 



A most exhaustive study of the mosquitoes of New Jersey has resulted 

 in the adoption of control measures which, wherever thoroughly carried out, 

 have greatly relieved the situation. Every district has its own particular 

 problem, usually intimately associated with peculiarities of topography and 

 special advantages offered to one or more species in the mosquito fauna. 

 In New Jersey the big problem lay in the salt marshes. At the high tides 

 the flooding of these resulted in the formation of shallow pools where the 

 salt marsh mosquitoes, .ffides sollicitans, .ffides cantator, and .ffides taenior- 

 hynchus, could develop unmolested by their natural enemies, mainly certain 

 fishes. By drainage the conditions so favourable to mosquito-development 

 were eliminated. Where complete drainage was not practicable, ditching 

 was undertaken in such a way that the controlling fishes could penetrate to 

 all breeding-places. 



