16 Annals Entomological Society of America [Vol. VI, 



4. Liberating Colored Adults. 



The experiments conducted on the canal zone suggest the 

 advisability of liberating adults at or about dusk, or from then 

 on till midnight. The stations selected may be few or many, 

 depending upon the complexity of the physical and biotic 

 factors presented at the time. All that is necessary for libera- 

 tion is for someone to open the lid of the cage containing the 

 colored mosquitos. This observer should note the time when 

 he liberated the mosquitos, the climatic conditions at the time, 

 and the direction taken by the mosquitos. If people move 

 about near the place of liberation, particularly after dusk, and 

 go to the town from there, this should be carefully noted. The 

 person delegated for this duty should be a keen observer, 

 and honest, too. 



The habits of the mosquitos vary with the species — not all 

 cry for the warm blood of man. Then there are some that 

 can't be without it. The writer liberated in the bush, about 

 one quarter miles from Corozal, Canal Zone, at eleven a. m., 

 about fifty stained Anopheles albimanus Wiede., and noted 

 three of these soon clinging to his dark colored trousers, and by 

 walking slowly — just as the natives do — he brought these with 

 him into the town of Corozal. This illustrates one of the 

 avenues of dispersal, practically independant of wind, and we 

 must reckon with it, especially since this species is responsible 

 for most of the malaria on the canal zone. 



A precaution, based on the above observation, was found 

 necessary. Brush your clothing carefully after liberating colored 

 mosquitos, and if possible, wear a light colored suit. The latter 

 suggestion proved very helpful. Note also if people passing 

 along the highways, walk toward or from the townsite, and 

 whether they saunter or walk fast, or are quiet or boisterous. 



5. Collection and Examination of Adults in Buildings. 



The recovery of liberated mosquitos in the buildings will 

 demand thorough search and great precaution. Unless this is 

 done, much fruit cannot be expected for the labors and patience 

 expended. 



A. Collection by Hand: Hand collections in the buildings 

 are best made at dawn and just at dusk, the mosquitos at these 

 two periods trying to get out and into, respectively, of the 



