222 The Control of Mosquitoes 



It has been ascertained that marked differences 

 exist in the habits and life history of different 

 Anopheles, and between Anopheles and other 

 mosquitoes. We learned how to observe their 

 flight, and that the malaria-carrying species can 

 be stained, and by this means it can be determined 

 how far and in what direction they travel; and 

 by intercepting them in the path of their flight, 

 they are made to register its general direction. 

 It was established that some species of Anopheles 

 travel farther than others. 



It was observed that while Culex, and possibly 

 other mosquitoes, enter a residence on the wind- 

 ward side, Isthmian Anopheles seldom do this. 

 The importance of placing screened entrances 

 and verandas on the windward side is now under- 

 stood, but had not previously been considered. 

 A method of making Anopheles trap and destroy 

 themselves has been perfected; and it has been 

 determined that some species avoid bright artificial 

 light. 



New methods of collecting specimens have been 

 devised. 



The migration of one species across the Isthmus 

 was closely observed. Previously it was thought 

 that malaria increased in proportion to the number 

 of Anopheles in a malaria-infested community, 



