326 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



with colored chalk (by shaking in a bag) and liberated at refuse ac- 

 cumulations about one-half mile from the village church were after- 

 ward recovered in the village. In fact they were able to recapture 

 marked flies at 1,700 yards and found that distances of 800 to 1,000 

 yards were often traversed and that flies would travel 800 yards in 

 thirty-five to forty-five minutes. Howard (1911)^ notes experiments 

 by Hine in which 350 flies were marked with gold enamel and recovered 

 during three days at distances of 600 to 1,200 yards. Hine is of the 

 opinion "that the distance flies may travel to reach dwellings is con- 

 trolled by circumstances. Almost any reasonable distance may be 

 covered by a fly under compulsion to reach jood or shelter. When these 

 are close at hand the insect is not compelled to go far and, consequently, 

 does not do so" (author's italics). Experiments by Forbes were also 

 recorded. Flies were sprayed with a chemical solution and recovered 

 up to a distance of one-fourth mile. They were identified by another 

 spraying with a solution which gave a blue color to those previously 

 sprayed. Doctor Howard states that "the house-fly -will seldom 

 travel very much farther than it has to fly for food and a proper nidus 

 for its eggs, but as a matter of fact, this is difficult to prove." Hewitt 

 (1912)^ conducted experiments at Ottawa during which 13,600 flies 

 were liberated during a period of nine days. These flies were sprayed 

 with a solution of rosolic acid. After recovery such flies when wetted 

 with a slightly alkaline solution became scarlet. The point of liber- 

 ation was near an isolation hospital on Porter's Island in the Rideau 

 River. One hundred and seventy-four flies were observed or recovered 

 at from 180 to 700 yards within nine days after the first release. It 

 was found that flies "were usually collected in that portion of the 

 district toward which the wind had been blowing from the direction of 

 the island, as it was found that the wind was the chief factor in determining 

 the direction of distribution" (author's italics). Doctor Hewitt further 

 states that "there is no doubt that given the necessary conditions with 

 regard to wind and elevation above the ground, the range would be 

 considerably greater than was actually found in these experiments." 

 Professor C. F. Hodge (1913)^ records plagues of flies at the cribs of 

 waterworks situated one and one-fourth, five and six miles respectively 

 out in Lake Erie. He concluded that they had been carried by the 

 wind and had gathered on the cribs as temporary resting places. These 

 observations concerned Sto77ioxys and Calliphora as well as the house- 

 fly. Hindle (1914)® gives the results of experiments conducted during 

 July, August and September of 1912. Over 25,000 flies were hb- 

 erated and fifty points established for their recovery. "The results 

 of these experiments point toward the following conclusions: (1) that 

 house-flies tend to travel either against or across the wind; this di- 



