UNITED STATES DEPARTMENT OF AGRICULTURE 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief Se? SS. 
Washington, D. C. PROFESSIONAL PAPER February 5, 1916 
NOTES ON THE PREOVIPOSITION PERIOD OF THE 
HOUSE FLY, MUSCA DOMESTICA L. 
By R. H. Hurcutson, Scientific Assistant. 
CONTENTS. 
Paze Page 
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INTRODUCTION. 
During recent years a great deal of emphasis has been laid upon 
the use of flytraps as a means of reducing and controlling flies. The 
popularity of trapping is based not only on the immediate results 
obtained, but also upon the claim that many female flies will be 
caught let ane they have laid their first eggs, and that thus the possi- 
ble number of future generations will be greatly reduced. For much 
the same reason it has been urged that trapping flies in the early 
spring is effective in reducing the number of future generations. An 
apparent justification for this method of control was found in the 
published records of experiments and observations indicating a rather 
long period of time between the emergence of the adult fly and the 
first deposition of eggs. 
Entomologists have been aware that these methods of control were 
founded upon a rather meager scientific basis. Comparatively few 
accurate data have been published bearing upon the length of the 
preoviposition period. The necessity of more data on this phase of 
the life history of the house fly was clearly pointed out by Dr. L. O. 
Howard (1911), and upon his suggestion work along these lines was 
begun during the season of 1913. The work has been carried out 
under the general direction of Mr. W. D. Hunter. A few experiments 
on the preoviposition period were carried out by the writer during 
the season of 1913 at Arlington, Va., and others during the spring of 
Notre.—This paper is intended for entomologists and others who are interested in the extermination 
of house flies. 
17268°—Bull. 345—16 
