﻿394 The Philippine Journal of Science wu 



BREEDING MOSQUITOES FROM THE LAEV^ 



The collected larvse were carried to the laboratory and placed 

 with the water in the breeding jars. These consisted of battery 

 jars, or large open-mouthed bottles, the tops of which were 

 covered with netting secured by rubber bands. These jars were 

 kept on the open veranda outside of the house. The sun-loving 

 species were placed where they would get a certain amount of 

 sunlight each day, and the shade-loving species were placed in 

 a shaded position. Every morning the laboratory assistant 

 aerated the breeding jars by passing a current of air to the 

 bottom of the jar, as recommended by Darling (1910) . A major- 

 ity of the pupae and large larvae always developed, but many 

 of the small larvae failed to develop from lack of food or for 

 other reasons. 



When the pupse had hatched and the mosquitoes had collected 

 in the upper part of the breeding jar, they were allowed to escape 

 into the biting cages. These latter consisted of lantern chim- 

 neys, as recommended by Darling (1910). The upper end of 

 the chimney was covered with mosquito netting fastened by 

 a rubber band, and the lower end was set into the half of a 

 Petri dish. The supply of a proper amount of moisture to sat- 

 urate the atmosphere, but not drown or sprawl the mosquitoes, 

 was a problem of considerable importance and difficulty. In open 

 dishes of water placed in the cages, the mosquitoes were fre- 

 quently drowned, even when a float of cork was placed on the 

 surface. In our earlier experiments small stender dishes, filled 

 with absorbent cotton over which were placed several layers 

 of filter paper, were filled with as much water as the cotton 

 would absorb. This served the purpose fairly well, but as the 

 hot season advanced the heavy mortality among the mosquitoes 

 led us to seek other methods that might prolong the life of 

 the insects. In an attempt to imitate natural conditions, the 

 Petri dish bottoms of the cages were filled with moist earth 

 containing a growing plant. This proved to be little, if any, 

 superior to the saturated cotton, and molds rapidly developed on 

 the moist earth. Finally the bottom of the cage was filled with 

 washed sand, which was kept saturated with water. This method 

 proved to be the most satisfactory. Sufficient water was sup- 

 plied, and the sand served as a resting place for the mosquitoes 

 without danger of drowing ; a large surface for evaporation was 

 furnished which saturated the atmosphere without condensation 

 on the surface of the glass, in which the mosquitoes become 

 sprawled; and there was no difficulty from the growth of molds. 



