io8 N. J. Mosquito Extermination Association 



stances it is likely to find breeding places near its food supply 

 and probably rarely returns to the place where it was bred. 



A small brood of salt-marsh mosquitoes (A. cantator and A. 

 sollicitans) vv^ill travel only a short distance for food and return 

 to the marsh for laying eggs, but a very large one will throw 

 off an immense number of migrants which will fly for long 

 distances over territory in which no suitable breeding ground 

 exists. Of course, such flights multiply the insects' chance for 

 obtaining food and also in some cases lead to new breeding 

 grounds. The fact that most of the migrants exhibit undeveloped 

 ovaries does not necessarily mean that breeding cannot take place 

 when the new breeding grounds are reached. 



It seems as if intense breeding over large areas is followed by 

 wide distribution of the adults of the house mosquito (Culex 

 pipiens), the fresh-water swamp mosquitoes {Aedes sylvestris) 

 and the salt-marsh mosquitoes {Aedes cantator and Aedes sollici- 

 tam). It is possible that under similar conditions Anopheles 

 (some of which carry malaria) would be found to act similarly. 



ExtkrnaIv i^actors which in:pi.ue:nce flight 



Without doubt low temperature reduces, may suspend, or 

 even destroy, the activity of the adult mosquito. Excessively 

 high temperatures always retard mosquito activity. A warm 

 temperature, 80° F., is extremely favorable. 



Light is avoided by most species and some have such an abhor- 

 ence of it that they will not become active while it is strong. 



Atmospheric moisture has a very powerful effect upon the 

 adult. High percentages are favorable and low percentages 

 deadly. Rain itself is decidedly injurious and prevents adult 

 mosquito activity. 



Air movements greatly influence mosquito activity. A stiff 

 breeze is usually quite sufficient to stop their movements and to 

 compel them to cling to shelter. Winds of low velocity (10 

 miles an hour or less), of high temperature (about 80° F.) and 

 high humidity appear to be the ones that favor long flights. 



The observations of practically all investigators indicate that 

 the salt-marsh species in long migrations travel with the wind. 



