June, '14] MORRILL: HOUSE-FLY BAITS AND POISONS 273 



even greater than did the addition of bread to formalin and to forma- 

 lin mixtures. 



Bichromate of potash sohitions gave practically no results either in 

 the tests of its attraction or of its poisonous qualities. 



Cobalt gave variable results in the tests but appeared rather pecu- 

 liarly attractive when used with bread and in one instance exhibited 

 better killing effects than formalin. 



Sweet milk without addition of other material seems to have little 

 if any advantage over sour milk in the point of attractiveness to flies. 

 Combined with bread sweet milk was strikingly attractive but not so 

 much so as were formalin or alcohol mixtures used with bread. 



Beer Avas found to be a very attractive bait for flies under certain 

 conditions. As already mentioned it combines readily with formalin 

 but not Avith alcohol. Fresh beer, contrary to the common' idea, was 

 found to be far more attractive than stale beer. 



Bread added greatly to the attractiveness of various liquid fly foods 

 and poisons. 



Wheat bran was found by the experiments here recorded and others 

 to be inferior to bread as a fly bait. 



Overripe or decayed banana was found to be superior to ordinary 

 ripe banana and to both good and decayed oranges and apples as a 

 fly bait. 



Commercial dried blood moistened with water was found in the 

 experiments to have attractive value greater than fresh and decom- 

 posed meat or fish. It is noteworthy that decomposed fish was found 

 to be much less attractive to house-flies than fresh fish. Blue bottle 

 flies and other species of the so-called flesh or meat flies were attracted 

 to these ''animal matter" baits, but only the true house-fly is herein 

 considered. 



Contrary to expectations cane s\'rup and sugar and water were found 

 to have relatively low attractive value when used without other 

 materials. 



The value of sticky fly paper was very materially increased by expos- 

 ing small amounts of attractive baits on the center of each sheet. 

 The tests show that a thin slice of overripe or decayed banana makes 

 an inoffensive and eff"ective bait for this purpose. 



Mr. T. J. Headlee: In the house-fly campaign in the City of New 

 Brunswick, N. J., "Hodge Fly traps" were placed on garbage cans. 

 Very few house-flies were caught but large numbers of green and blue 

 bottle flies were secured. We experimented with various kinds of 

 bait. Milk and bran bait is the best we have found, but we did not 



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