326 preventive and remedial measures 



The Destruction of Adult Flies. 



Many means have been devised whereby the adult flies may 

 bo destroyed and, while the prevention of their breeding constitutes 

 the fundamental principle of their control, the destruction of the 

 flies must naturally form a part of any system of eradication. 



The methods of destruction may be divided into two classes : 

 trapping and poisoning. 



Trapping. 



There are on the market and in use a great variety of fly-traps 

 the majority of which have proved successful. Such forms as the 

 glass fly-traps baited with beer and the balloon wire trap baited 

 with any attractive bait are well-known. The sticky fly papers, 

 ribbons and wires need no description. 



p 

 Fig. 101. The Minnesota Fly Trap. General view and cross section. 

 (After photograph by Washburn.) 



Parrott has devised a trap which consists of a shallow tin box 

 having sides about three-quarters of an inch deep : it is made 

 long enough to fit in the bottom of the window pane. After 

 these shallow boxes have been fitted they are filled about two- 

 thirds full of some insecticidal substance such as paraffin or 

 kerosene, or an emulsion of the same, or a sticky mixture of equal 

 parts of castor oil and resin made by boiling the two constituents 

 together. 



The " Minnesota Fly Trap " which has been devised by 

 Washburn (1912) has pi'oved successful in the trapping of flies 

 in large numbers. On the back porch of a dwelling, not far from 



