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Journal of Agricultural Research 
Vol. XXI, No. io 
out under urban conditions by Copernan, Howlett, and Merriman in 
1911. 1 
Parker’s experiments in Montana were also carried out largely under 
city conditions. The greatest range of dispersion shown in his tests was 
3,500 yards, or nearly 2 miles, with the house fly. A record of 500 yards 
was made for Muscina stabtilans Fall., and 160yards for the black blowfly 
(Phormia regina Meig.). These last species, however, were released in 
comparatively insignificant numbers. 
In addition to exact evidence obtained by recapturing marked and 
released flies, other evidence of dispersion is at hand. Hodge 2 has 
observed house flies, stable flies (Stomoxys calcUrans L.)> and “ blue 
bottles” in considerable numbers at cribs 5 and 6 miles out in Lake Erie 
north of Cleveland, Ohio. He concludes that the flies appear to be 
blown out at least 6 miles off shore. In 1917, Ball 3 presented evidence 
which indicates that the house fly may go distances of 45 or 95 
miles. These observations were made at the Rebecca Light v Shoal 
off the coast of Florida, and the conclusion was reached that the 
flies came down wind from Cuba (95 miles distant) and at times from 
the Marquesas Keys (24 miles distant) or possibly from Key West, Fla. 
(46 miles distant). While the evidence of flight over these long distances 
is convincing it is hardly incontrovertible. The flight in these instances 
was over water, at least for the most part; hence the conditions were very 
different from those existing under usual urban or rural conditions. 
With a view to securing some definite facts as to the tendencies and 
possibilities of dispersion under rural conditions, a series of tests with 
injurious species was carried out in northern Texas during the summers 
of 1916 and 1918. 
METHOD OF CATCHING, MARKING, AND LIBERATING FLIES 
Practically the same method of handling the flics was used throughout 
the several tests conducted. The supply was secured by baiting large 
conical flytraps with “gut slime,” a packing house by-product. These 
traps were left in operation from a few hours up to 24 hours; then a screen 
cylinder was placed on top of the flytrap. The cover of the trap was re¬ 
moved, and the flies were agitated so that they would pass upward into 
the cylinder, which was first supplied with a number of green branches 
from trees. Few of the weaker, disabled flies would pass upward into 
the cylinders. When several thousand had passed into the cylinder a 
cheesecloth was placed over the lower end of it. All the flies were 
1 Copeman, S. Monckton, Howlett, F. M., and Merriman, Gordon, an experimental investiga¬ 
tion on TIIE RANGE OF flight OF Flies. In Rpts. Local Govt. Bd. [Gt. Brit.] Pub. Health and Med. 
Subjs., n. s. no. 53, p. 1-9. 1911. 
2 Hodge, C. F. the distance house flies, blue bottles and stable flies may travel over water. 
In Science, n. s., v. 38, no. 980, p. 512-513. 1913. 
3 Ball, S. C. migration of insects to rebecca shoal light-station and the tortugas islands, 
with special REFERENCE TO mosquitoes and Flies. In Papers I)ept, Mar. Biol. Carnegie Inst. Wash., 
v. 12 (Publ. 252), p. 193-212. 191S. Bibliography, p. 212. 
