﻿430 The Philippine Journal of Science 



Table X. — Development of ova in the experimental mosquitoes. 



1914 



Species. 



Anopheles febrifer 



Anopheles rossii 



Anopheles barbirostris 



Anopheles sinensis 



Anopheles maculatus. . 



Total 



Ova de- 

 veloped. 



9 

 17 

 43 







4 



73 



Ova not 



de- 

 veloped. 



381 



541 



154 



18 



45 



1,139 



Percent- 

 age hav- 

 ing ova 



de- 

 veloped. 



2.3 

 3.1 



27.9 







8.0 



6.4 



Annett, Dutton, and Elliott (1901) performed a number of 

 experiments on the relation between a blood meal and the 

 development of ova in anopheline mosquitoes; and from these 

 experiments they came to the conclusion that a blood meal was 

 necessary for the development of ova in the female. It would 

 seem that the converse of this might be true ; that every female 

 which had a blood meal and copulated with a male would de- 

 velop ova. It was hoped that the presence of developed ova 

 might supply an index of whether or not the mosquito had bitten 

 a patient and sucked blood, but this does not appear to be the 

 case. 



PERCENTAGE OF INFECTED JIOSQUITOES 



Of the total 1,287 female anopheline mosquitoes dissected 

 after having had one or more opportunities of taking a meal 

 of blood containing gametes, 205, or 15.92 per cent,, contained 

 oocysts in their mid-guts, or sporozoites in their salivary glands, 

 or both oocysts and sporozoites, depending upon the time elaps- 

 ing between the date of feeding and the date of dissection. Of 

 the 205 infected mosquitoes, 189 contained oocysts in their mid- 

 guts in various stages of development, and 28 showed sporo- 

 zoites in their salivary glands. In experiments 1 to 94, the 

 females containing blood were not separated from the empty 

 females and it was impossible to make any differentiation at 

 the time of dissection, but in experiments 95 to 227a only the 

 females containing blood were dissected; in this series the pro- 

 portion of infected females should be considered separately. 

 Furthermore, a still more reliable comparison of the infections 

 in the several species will be obtained by considering separately 

 certain parallel experiments in which the different species of 

 mosquitoes were fed at the same time on the same patient, in 

 which the females containing blood were separated, and in 



