INSECTS OF THE HOUSEHOLD 



69 



Fig. 25 a 



At the beginning of the lesson restate the question and 

 allow only a few minutes for them to advance their own 

 theories. Follow up the answers that take the right direc- 

 tion and see if the .cases of malaria cannot be accounted 

 for readily by 



means of trans- 

 mission of the dis- 

 ease by mosquito 

 bites. Then read 

 the following : 



" The latest an- 

 nounced results of 

 the most advanced in\estio^ators 

 seem to show that mosquitoes 

 form the principal if not the sole 

 means of transmission of malaria, 

 and workers in all parts of the 

 world, including many parts of 

 the United States, are investigat- 

 ing the subject, more especially 

 in relation to local conditions." 

 Circitla?' No. 40, Second Series, 

 United States Department of 

 Agriculture, Division of Ento- 



Half-Grown Larva of Anopheles 



In feeding position, just beneath surface film. 

 (Enlarged. After Howard) 



Fig. 25 /'. 



Half-Grown Larva of 



CULEX 



In breathing position. (Enlarged. 

 After Howard) 



mology, entitled " How to distin- 

 guish the Different Mosquitoes 



of North America." [It is now held that yellow fever is also trans- 

 mitted by mosquitoes.] 



The children will see that they are doing something 

 worth while and of present interest. It now becomes 

 necessary to distinguish among the different species of 

 mosquitoes the ones that carry malaria. These have all 

 been found to belong to the genus Anopheles. The 



