22 



THE HOUSE FLY 



The excreta of a fly on our food is bad enough, but when 

 we learn that this excreta, in a large number of cases, is 

 seething with living disease microbes, then indeed it is a 

 matter for earnest thought, and prompt action. A single 

 fly speck may contain the germs of any disease man and 



FIG. 9 



THE HEAD OF A HOUSE FLY, seen from above. 

 i. The compound eyes studded with thousands of facets which 

 enable the fly to see in all directions. 2. Three simple 

 eyes in the centre of the top of the head. These give 

 the fly extra powers of vision. 3. The antennas or 

 " feelers." 4. The proboscis or sucker. 

 {From National Geographic AJagazine, Washington, D.C. 

 Copyright 1913, by special permission.) 



his domestic animals is subject to. The fly speck may 

 harden by exposure on a plate, a knife, on food, or on a 

 variety of other things, but the microbes in it are by no 

 means dead. They are, for the present, incapable of doing 



