10 HOUSEHOLD INSECTS 



HOW FAR CAN THE ADULT FLY ? 



The question of how far this insect will fly from its 

 breeding place has an important bearing upon methods 

 of fighting it. Moreover, the area that it can cover in 

 a neighborhood has an important bearing upon its dangers 

 as a disease-germ-carrying instrument. It is held by 

 observers, in general, that house-flies, under normal con- 

 ditions, do not fly far. However, when aided by winds 

 they may go considerable distances. Arnold, of the 

 Monsall Fever Hospital in Manchester, captured 300 

 flies and marked them with a spot of white enamel on the 

 back so that he could identify them. He liberated these 

 in fine weather and during the next five days captured 

 5 out of the 300 in traps, all within 30 to 190 yards from 

 the point of liberation. Hewitt says he has seen them 

 flying at a height of 80 feet and remarks that this would 

 greatly facilitate their carriage by winds. 



In an experiment by Copeman, Howlett, and Merriman, 

 three English investigators, on the range of flight of flies, 

 they recovered marked specimens at distances varying 

 from 400 to 1408 yards and, in one case at least, at a 

 distance of 1700 yards. This indicates a flight of nearly 

 a mile. It shows that the breeding places within a mile 

 of a given building must be abolished if the flies are ex- 

 terminated. 



C. F. Hodge has found house-flies very numerous on 

 the cribs of the Cleveland waterworks six miles out in 

 Lake Erie. These flies could not possibly have bred on 

 the cribs and the only conclusion is "that the flies are 

 blown at least six miles off shore." 



