636 EVERYDAY SCIENCE 



ace exactly as we wonder at the unsanitary living conditions com- 

 mon centuries ago. 



The average life of a fly is about three weeks. Most of the 

 millions of flies that do not die of natural causes during the summer 

 succumb to fungous diseases in the fall or to the cold of early winter. 

 But in almost every house a few survive. They hide in all sorts of 

 warm crevices, where they pass the winter in a state of complete 

 rest. The number of flies that may be descended in one summer 

 from one wintered-over fly runs into the trillions ! The moral is : 

 clean and disinfect every crevice of your house in March and swat 

 the wintered-over fly. 



Screen all porches, windows, and doors in fly time. 



Make all vaults fly-proof with screening, and cover the contents 

 once a week with copperas or iron sulphate to disinfect them and 

 to prevent the development of fly maggots. 



Keep all garbage covered tightly until it is disposed of. To kill 

 all flies in and around garbage pails, sprinkle formaldehyde solution 

 1 part formalin to 10 parts water in and around the pails once 

 a week. 



Make traps and set them near doors and other places where flies 

 congregate. Patterns and detailed instructions for making an 

 effective fly trap may be had by sending five cents in stamps to 

 the Agricultural Extension Department of the International Har- 

 vester Company, Chicago. See also Farmers' Bulletins Nos. 734 

 and 927. 



All flies breed in filth. Ninety per cent of all flies breed in stable 

 filth ! This should be hauled away and spread as fertilizer at least 

 once a week. If this cannot be done, keep it in tightly covered 

 boxes or pits until it is removed. Farmers' Bulletin No. 851 gives 

 detailed instructions for the extermination by some means or other 

 of flies that breed in stable filth. See that ordinances are passed and 

 enforced against all people who maintain live stock in a community. 



For organizations that wish to conduct a fly campaign, the fol- 

 lowing books and pamphlets will prove of great value : 



"Farmers' Bulletin" No. 851. This treats of the life history of 

 the fly, of its carriage of disease, its natural enemies, control measures, 



