﻿424 



The Philippine Journal of Science 



1914 



The data are probably approximately accurate for the first 

 3 species, but in the last 2 the numbers are too small for the 

 percentages to be reliable. 



THE AVIDITY OF THE SEVERAL SPECIES OF ANOPHELINES FOR HUMAN BLOOD 



In experiments 1 to 94, inclusive, the females which contained 

 blood were not separated from the empty females and males 

 after feeding on infected blood; the mosquitoes in this series 

 were usually given two or more opportunities to feed on the 

 malarial patient on successive days. It is, therefore, impossible 

 to say what proportion of the mosquitoes in this series fed on 

 the infected blood at any one time. In experiments 95 to 227a, 

 inclusive, the mosquitoes, which were given an opportunity to 

 bite the infected patient only once, were immediately removed 

 individually from the biting cages in test tubes and examined 

 with a hand lens. The females containing blood were separated 

 from the empty females and the males, and were placed in a 

 separate cage which was given the experiment number. The 

 number of females containing blood, empty females, and males 

 were, in most cases, recorded in this series of experiments. In 

 Table VI are given the results of these differential counts, clas- 

 sified according to the species of Anophelinas. Some of these 

 mosquitoes were fed on the malarial patient within twenty-four 

 hours, others not until the second day after emergence. In 

 the latter case, all food was usually withheld from the mosquitoes 

 until they were fed on the malarial patient. 



Table VI. — The proportion of the different species of anophelines taking 

 a meal of blood when given one opportunity. 



Species. 



Anopheles febrifer 



Anopheles rossii 



Anopheles harbirostris 



Anopheles sinensis 



Anopheles maculatxis-- 



Total - — 



Total 

 females. 



696 



936 



273 



59 



2 



Females 



containing 



blood. 



382 



596 



135 



40 



1 



1.966 



1,154 



Empty 

 females. 



314 



340 



138 



19 



1 



Taking a 



meal of 



blood. 



Per cent. 

 54.8 

 63.6 

 49.4 

 67.8 

 50.0 



812 



58.69 



From these data it appears that, as a whole, slightly over half 

 of our mosquitoes took a meal of human blood when given one 

 opportunity from twelve to forty-eight hours after emerging 

 from the pupse. In some instances the mosquitoes bit well on 



