HABITS OF THE ADULT FLY 49 



article, that the fly in question was a house fly, but 

 upon consulting- an important paper by the same author 

 (1906), entitled "Fungous Maladies of the Sugar 

 Cane," the same table is found printed on page 64 

 and the fly in question is said to be a Sarcophagid, 

 and therefore not Musca domestica. In his opening 

 paragraph in the 1910 article, Doctor Cobb explains, 

 "In some of these paragraphs, however, the statements 

 are inferences fully justified by experiments with very 

 similar species," and this table is evidently one of these 

 inferential statements. It is not safe to state that be- 

 cause, as shown in the table, a well-fed Sarcophagid 

 fly will defecate on the average once every four and 

 one-half minutes, from half past nine until half past 

 eleven, a true Musca will do the same. It is by no 

 means impossible that it will do so, but unfortunately 

 we have not the proof. Still with this explanation it 

 will be interesting to state that in the interval between 

 9: 35 and 11:26 the fly observed by Doctor Cobb (it 

 had been fed at 9 : 23) made twenty-three fly-specks at 

 intervals varying from one to fifteen minutes, an av- 

 erage of about four and one-half minutes ; and in ten 

 of these twenty-three specks Doctor Cobb found spores. 

 Herein lies one very great danger from flies. Certain 

 authors believe that the danger from disease germs 

 that pass through the fly's body in this way is greater 

 than from those that are supposed to be carried from 

 foul substances on its feet. 



With the abundance of flies in the late summer, the 

 number of fly-specks becomes almost unlimited. Doc- 



