380 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



the germs are carried and distributed to other substances over 

 which it may walk, and that bacteria may live in the alimentary 

 canal of the fly and even increase in numbers there and remain 

 virulent in the excreta, or "fly specks," for as long as twenty 

 days after these specks have been deposited. It has been 

 shown also that larvae of flies may feed on bacteria and the 

 same organisms be recovered from the adult flies which develop 



FIG. 1 68. Foot of house-fly, showing claws, hairs, pulvilli and 

 minute clinging hairs on the pulvillas. (Greatly enlarged.) 



the 



from the larvae. All this indicates some of the possible ways in 

 which flies may carry filth or disease germs from their dangerous 

 breeding or feeding grounds directly to foods which may be 

 exposed in the market place, dairy, or home. 



It has been proved beyond a doubt that flies play an impor- 

 tant part in the dissemination of typhoid germs, and it has 

 also been shown that they carry some of the germs that cause 

 the sickness and death of many babies, especially bottle-fed 

 babies. Time and again it has been noted that outbreaks of 



