1913] 



Determining the Flight of Mosquitos 



13 



Frequently through chemical or physical changes in the 

 water, produced by excess of heat or food, improper food or 

 foreign substances, waste, etc., the larvae become sluggish and 

 pupation is greatly retarded. If the cause is not due to fouling 

 of the water, then table salt added not in excess of three percent, 

 will make the larvae active and accelerate pupation. The 

 dead or sick larvae in such pans should be eliminated. 



Pupae should be segregated from the breeding dishes daily, 

 preferably morning and evening. They should be confined in 

 wide-mouthed jars, the depth of water not exceeding" one and 

 one half inches, and the number of pupae not more than two 

 hundred and .fifty. The mouths of these jars should be pro- 

 vided with paper cones, the tip truncated, and both cone and 

 neck of the jar inserted into a screen cage as shown in figure 3. 



Fig. 3. Breeding-out Cage.S, screen cage, hinged back; A, wooden "H" sup- 

 ports; R, lofts for wetted waste; T, jar containing pupae; E, truncated paper cone 

 trap. 



The cone acts as a trap, thus preventing the adults which enter 

 the cage from returning into the jar and being drowned. All 

 crevices about the jars and in the cages must be stopped with 

 cotton waste. 



It is advisable to place moist cotton on the floor of the screen 

 cage, also to fill cavities "A" of the "H" supports with wet 

 waste. The top ought to be covered with a wet cloth. These 

 simple measures keep the inside of the cage cool and sweet, 

 and adults can be kept in good condition for at least six days. 

 The cages must be protected from direct sunlight, heat and rain. 

 If ants are present, isolation by water barriers is necessary. 



