Flight and Attraction of Mosquitoes in 



stained with an aqueous solution of an aniline dye. 

 They were given a period of rest and liberated 

 toward evening. Aqueous solutions of eosin, me- 

 thylene-blue, etc., were used, one gram of dry stain 

 to fifty cubic centimeters of water. An atomizer 

 was used to direct a fine spray upon the mosquitoes. 

 When spraying care was taken to avoid covering 

 them entirely with the stain ; only minute particles 

 were allowed to touch them. It was found that too 

 much stain rendered the mosquitoes useless 

 for purposes of experimental flight. The stained 

 mosquitoes were liberated at known distances 

 from the laborers' barracks at Corozal and to the 

 south of it. All mosquitoes noted in the building 

 at that camp were carefully collected; those from 

 each house placed in a separate box, dated and 

 labeled. Later they were placed on a glass plate 

 that rested on white paper and spread out. Each 

 one was treated with a small amount of a solution 

 that dissolved the dye on any stained specimen. 

 When stained specimens were encountered, the 

 color was seen to be present as soon as the testing 

 solution came in contact with it. The solvent 

 for testing consisted of three parts alcohol, three 

 parts glycerine, and one part chloroform. As a 

 result of this method of staining and consequent 

 ability to follow the movement of mosquitoes 



