532 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



THE EFFECT OF CERTAIN CHEMICALS UPON OVIPOSITION 

 IN THE HOUSE-FLY (MUSCA DOMESTICA L.)^ 



By S. E. Crumb and S. C. Lyon 



During the summer of 1916 the writers conducted a series of ex- 

 periments with house-flies to learn, if possible, what substances in 

 horse manure were capable of inciting them to oviposit. In the course 

 of these experiments it was learned that the ether extract possessed 

 this quality in some degree but that the chief incitant remained after 

 complete ether extraction and was a product of fermentation. Fur- 

 ther investigation gave positive evidence that this oviposition stimu- 

 lant was carbon dioxide. A limited series of experiments with am- 

 monia gave negative results. 



As the conclusions to be drawn from our experiments did not agree 

 with those of Mr. Richardson^ it was decided to devise an apparatus 

 for more thoroughly testing the effect of ammonia on fly oviposition 

 and the experiments both with ammonia and carbon dioxide have been 

 continued during the present summer. 



The ammonia-testing apparatus (see Fig. 27) consists of a water 

 tank of galvanized iron 7 feet long, 6 inches wide, and 9 inches high 

 set on six legs about 3 feet high and provided with nipples every foot 

 along the bottom. Each of these nipples is connected by tubing with 

 a six-quart can which rests on the table beneath the tank and may be 

 called the compression chamber. This compression chamber is fur- 

 ther connected with a pint milk bottle by means of a glass tube which 

 dips beneath the surface of the liquid in the bottle. This bottle rests 

 on the table in front of the compression chamber and contains the 

 ammonia or water used 'in the experiments. The exit from the milk 

 bottle is through an upright glass tube bearing at its apex a porcelain 

 drying funnel about three and one-half inches in diameter. This fun- 

 nel has a fixed perforated, porcelain partition about one inch below the 

 lip which bears the material provided as a nidus. 



The flow of water from the tank to the compression chamber is 

 regulated to any desired amount by adjustable clamps on the connect- 

 ing rubber tubes and, as all connections in the apparatus are air-tight, 

 an amount of water admitted to the compression chamber displaces 

 an equal amount of air through the material in the funnel after it has 



1 Published by permission of the Chief of the Bureau of Entomology. 



2 Charles H. Richardson. The Response of the House-Fly to Ammonia and 

 Other Substances. Bull. 292, New Jersey Ag. Ex. Sta., Feb. 1, 1916. A Chemo- 

 tropic Response of the House-Fly (Musca domestica L.). Science, new series, vol. 

 43, 613, April 28, 1916. 



