HABITS OF THE ADULT FLY 55 



he captured some 350 flies and marked each one's wing 

 or thorax with a small spot of gold enamel. Flies so 

 marked were repeatedly observed about dwellings from 

 twenty to forty rods from the barn up to the third day, 

 but in a dwelling house a half mile away none of the 

 marked specimens was detected. This, however, was a 

 very unsatisfactory experiment, because it does not in 

 the least show that if the dwellings twenty to forty 

 rods from the barn had not existed flies would not have 

 been found in the dwelling half a mile away. As Hine 

 himself states, "It appears most likely that the dis- 

 tance flies may travel to reach dwellings is controlled 

 by circumstances. Almost any reasonable distance may 

 be covered by a fly under compulsion to reach food or 

 shelter. Where these are close at hand the insect is 

 not compelled to go far, and consequently does not 

 do so." 



Hewitt is of the opinion that normally house flies 

 do not fly great distances, and compares them to do- 

 mestic pigeons which hover about a house in the im- 

 mediate neighborhood. He states that they are able 

 to fly, however, for a considerable distance and can be 

 carried by the wind. At one time when he was vis- 

 iting the Channel Islands he found the house fly from 

 one and one-half to two miles from any house or any 

 likely breeding place that he was able to find. He 

 mentions some exact experiments made by Dr. M. B. 

 Arnold at the Monsall Fever Hospital, Manchester, 

 where 300 flies were captured alive and marked with a 

 spot of white enamel on the back of the thorax. They 



