46 The Control of Mosquitoes 



various villages, ship them across the Isthmus, and 

 have them arrive in their normal healthy condi- 

 tion. It was found absolutely essential to keep 

 them shaded from sunlight, rain, and strong air 

 currents. They appear to die rapidly if placed in a 

 drying wind, which apparently causes evaporation 

 that is fatal to them. The adults die if left 

 overnight in mosquito-bars out in the open. If 

 transported in cages few will die if the cage is 

 completely covered with paper. 

 ' In the biting experiments made by Dr. Darling 

 to determine which of the Isthmian Anopheles 

 were malaria carriers, seventy per cent, of the Ano- 

 pheles albimanus used became infected, about sixty 

 per cent, of the Anopheles tarsimaculata, and thir- 

 teen per cent, of the Anopheles pseudopunctipennis. 

 No Anopheles malefactor became infected although 

 several bit the same person who infected the Ano- 

 pheles albimanus. The conclusions drawn were: 

 that Anopheles albimanus was the all-important 

 transmitter of malaria fever in the Canal Zone at 

 the time the experiments were made. Anopheles 

 tarsimaculata was probably as susceptible to in- 

 fection as Anopheles albimanus. The former, 

 however, had a much more limited geographical 

 distribution at that time, and appeared to be 

 ntimerous only near Colon on the Atlantic coast. 



