JOURNAL 



OF 



ECONOMIC ENTOMOLOGY 



OFFICIAL ORGAN AMERICAN ASSOCIATION OF ECONOMIC ENTOMOLOGISTS 



Vol. 14 DECEMBER, 1921 No. 6 



FURTHER OBSERVATIONS ON THE EFFECT OF CERTAIN 

 CHEMICALS UPON OVIPOSITION IN THE HOUSE FLY 



{MUSCA DOMESTIC A.) 

 By S. E. Crumb and S. C. Lyon, Bureau of Entomology 



In a previous article^ dealing mainly with the efifect of carbon dioxid 

 and ammonia on house-fly oviposition, the writers described the general 

 conditions under which the experiments discussed in the present article 

 were continued during the summers of 1918 and 1919. 



The substances used in the present series of experiments, however, are 

 less volatile than those used in the previous ones and for this reason the 

 writers dispensed with the compressed-air chambers previously described 

 and placed the funnels bearing the oviposition mediiim. over milk bottles 

 one-third full of tap water. In these cases the attractant was applied 

 in solution direct to the meditun., which was bran husk washed and 

 sterilized as before immediately previous to use. The checks used in 

 all cases were treated in exactly the same manner, excepting that they 

 received a corresponding volum.e of tap water instead of the solution 

 of the attractant. 



Ordinarily a row of 12 units of the foregoing apparatus was employed, 

 the water-treated checks alternating with the attractant used at the 

 time. Occasionally when the total number of flies in the cage was 

 small, only six units, three of the check and three of the attractant, 

 were used. 



It seemed better to adopt a standard check against which to try all 

 attractants than to endeavor to work out any scheme of checking by 



'Crumb, S.E. and Lyon, S.C. The effect of certain chemicals upon oviposition 

 in the house-fly (Musca domestica L.). In Journ. Econ. Ent., V.IO, no.6, p..532-536, 

 fig. 27. 1917. 



461 



