362 LIFE STORIES OF AUSTRALIAN INSECTS. 



House flies are pests, for they alight on decaying 

 animal and vegetable matter, on filth laden 

 with germs. These germs are transferred to the 

 hairs on the feet and body of the fly and then 

 transmitted to the exposed food in houses. Thus 

 disease may be spread. Hence the importance of 

 burning or covering up all waste organic matter. 



If one catches a fly and places a leg under the 

 microscope, one can see why the fly is so capable 

 of carrying disease germs. The legs are clothed 

 with numerous hairs; its feet also are rich in 

 hairs, and have two curved claws on the last tarsal 

 joint of each foot. Beneath the claws is a pad, 

 which is a hollow sac secreting a sticky fluid. On 

 the lower surface of the pad there are a number 

 of hollow hairs, through which the sticky solution 

 secreted by the pad issues in sufficient quantities 

 to allow the fly's feet to adhere to a smooth 

 surface without actually sticking. This is why 

 flies can walk on the ceiling and up smooth panes 

 of glass. The claws are used when a fly is walking 

 over a rough surface. 



We might remind our junior readers that a fly 

 is a '^ grown-up" insect no matter how tiny it 

 may be. The fly-babies are the maggots. Should 

 there be tiny flies it means that it is a different 

 species; or in some cases it may be a poorly-fed 

 specimen — the maggot or larval stage being with- 

 out the proper food-supply. 



