INSECTS AND DISEASES 405 



4. Place a counted number of wigglers in a dish of water 

 with a fish. Notice how long before they are all eaten. In 

 another dish put some wigglers with a tadpole and note results. 

 Try various kinds of water insects and see which ones eat the 

 wigglers. 



5. In another dish containing larvae and pupae, pour a few 

 drops of kerosene on the surface of the water. How long before 

 you note any results ? 



COMMUNITY PROJECT 3 



Purpose. To see what the class can do to help rid the locality 

 of mosquitoes. 



Directions. I. The class may be divided into groups, each to 

 supervise a certain section of the city. Aid of other agencies in 

 town such as newspapers, civic organizations, and health officers 

 should be sought so that all may cooperate for the best results. 



2. The class may first make a survey to see what breeding 

 places there are in the locality and which of them contain 

 wigglers. A map should be made to show this. 



3. The next step is to apply remedies. Is it feasible to have 

 any of the breeding places drained or filled? Which ones can 

 be covered ? On which can kerosene be used ? 



i. HARM DONE BY FLY 



Method of doing harm. Until recently the house fly has 

 been considered merely a nuisance, but investigations of 

 the past few years, have proved that it is a positive source 

 of danger as a means of carrying diseases. The method by 

 which it carries these is very different, however, from that 

 of the mosquito in carrying malaria and yellow fever. The 

 kinds of diseases usually transmitted by the flies are those 

 which may be taken into the system through food and drink. 

 The fly breeds in filth and frequents filthy places. As it 

 walks over these places, there adhere to its feet and the hairs 

 on its body, small particles of filth which often contain those 

 bacteria that cause disease ; and still other bacteria may be 



