The malarial fevers, haemoglobinuric fever and the blood protozoa of man . hosts for the plasmodia,but some species can only act as host for a certain species of plasmodia; thisfact has been proven again and again and serves to explain why certain typesof malaria are limited to certain localities. In Japan it has been found thatAnopheles formosaensis and Anopheles cohaesus can only transmit the aestivo-autumnal infections, while Anopheles jesoensis is able to act as a host for both 76 THE ETIOLOGY OF THE MALARIAL FEVERS. the benign tertian and the aestivo-autumnal infections. On the other hand
The malarial fevers, haemoglobinuric fever and the blood protozoa of man . hosts for the plasmodia,but some species can only act as host for a certain species of plasmodia; thisfact has been proven again and again and serves to explain why certain typesof malaria are limited to certain localities. In Japan it has been found thatAnopheles formosaensis and Anopheles cohaesus can only transmit the aestivo-autumnal infections, while Anopheles jesoensis is able to act as a host for both 76 THE ETIOLOGY OF THE MALARIAL FEVERS. the benign tertian and the aestivo-autumnal infections. On the other hand,Anopheles maculipennis, the most common mosquito occurring in temperateregions, is able to transmit tertian, quartan, and aestivo-autumnal malaria. While at the present time the malarial mosquitoes are more or less localizedin their distribution and certain types of malaria are thus confined to limitedregions, the increase of transportation facilities and of commerce will inevitablylead to a more general distribution of these insects, and thus regions free from .--~P^. Fig. 22.—Showing characteristics of Scales on various portions of body of different speciesof the Anophelinae, which have been proven to transmit malaria. I, Anopheles; 2, Myzomyia; 3, Pyretophorus; 4, Cellia; 5, Myzorhynchus; 6, Nyssorhynchus.(Arranged from Theobald.) malarial infection will become infected, and the more severe types of malaria,the aestivo-autumnal, will invade territory hitherto infected with the benigntertian type. Number of Species.—Nearly 1000 species of mosquitoes have beendescribed, of which the Anophelinae number some 150 species. Most of theseinsects are wood dwellers and do not come in contact with man, but it is probablytrue that most, if not at all, of the Anophelinae which are capable of transmittingthe malarial fevers are semi-domesticated species, and prefer to live withinreach of human habitations. THE ETIOLOGY OF THE MALARIAL FEVERS. 77 Literature upon the Development of the
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