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conclusively proved that they can not live in fresh water, nor in salt 

 water which has been brought up to the point of saturation. Certain 

 species of alga? are always found in salt water where Myzomyia ludlowii 

 Theob.. breeds. The commonest of these forms are Enteromorpha sp. 

 indet. and Chaetomorpha sp. indet. 3 and the cells of these plants are 

 found in the mosquitoes' stomachs. The insects are top feeders and 

 make little or no use of the slimy algae which grow upon the muddy 

 bottoms of the pools or ditches in which they live, unless the water has 

 so far receded as to bring these plants to within half a centimeter of the 

 surface. Few other water plants are found in the breeding places of 

 Myzomyia ludlowii Theob., but these, where they occur in small quantity, 

 do not ajmear to affect the larvae. The fact that none of the latter are 

 found in water the surface of which is covered more or less completely 

 with leaves of aquatic plants, goes to prove further that these insects 

 in the larval and pupal stages thrive best under the almost uninterrupted 

 glare of the sunlight, and that they retire to the shaded places only at 

 the time of metamorphosis, when they remain below the surface for con- 

 siderable periods before they came to the top to breathe. 



In laboratory breeding experiments the plants in the water begin to 

 die within three to five days, while the larvae appear to feed in a desul- 

 tory manner. The time for their natural transformation to the pupa 

 comes and goes and they still remain as larvae. The foulness of the 

 water, due to organic decomposition, appears not to affect them, but on 

 the other hand, the lack of proper food seems to cause them to remain 

 in an indefinite larval stage, until after three weeks or more they grad- 

 ually begin to die. Pupae brought in and kept under similar conditions 

 develop normally and the mosquitoes emerging from them appear not 

 to have suffered from lack of sunshine in their previous stage. The 

 conclusions are, therefore, that direct sunlight is absolutely necessary 

 for the best development of this mosquito. 



In Older to obtain a sufficient number of individuals for experiments in biting, a 

 large, white, gauze net was built over a pond the area of which was approximately 

 7 square meters. This net was high enough so that a man could enter by stooping 

 down, and go from one part of the inclosure to the other on boards about 15 cen- 

 timeters above the surface of the water. The earth banked up inside and outside 

 the net held it in place and kept the mosquitoes from creeping out beneath the 

 flaps; it also served as a resting place for the newly emerged adults. They were 

 never found upon the net itself, but always upon the earth, and being so nearly of 

 the same color it was not an easy matter to find them. 



While there was no appreciable difference in the appearance or rate of develop- 

 ment of the larvae, the adult mosquitoes were of a slightly paler color when they 

 were reared under nets and for some reason appeared to be less active or wary than 

 those individuals encountered in the open. 



Care was taken in constructing the net to exclude all small fish that might 



3 1 am indebted to Dr. W. R. Shaw, Philippine Normal School, for these iden- 

 tifications. 



