260 THE HOUSE FLY DISEASE CARRIER 



from the seeds of sugar beets stored in a mill; also 

 from larva? found with other larva? on the roots of roses, 

 as well as from under the bark of a post-oak pole. Ex- 

 act observations have been made here showing that the 

 larva is undoubtedly carnivorous : it has been fed upon 

 the larvae of stored grain insects, and when found in 

 woolen goods and under carpets it is undoubtedly in 

 search of clothes moths upon which to feed. 



The larva is long, white, and snake-like in shape, 

 with a dark head. It apparently has many segments to 

 the body, since each of the abdominal segments is di- 

 vided by a strong constriction. In feed stores the flies 

 are nearly always to be found around the windows, 

 and the probability is very strong that they feed upon 

 such small soft-bodied creatures as flour mites and 

 beetle larvae. 



Nothing definite has been ascertained concerning the 

 duration of the different stages, but from larvae taken 

 in January adults issued in April, and from larvae re- 

 ceived April 1 8th adults issued on the Qth of June; 

 with larvae received August 6th, one changed to pupa 

 on August 25th, another on August 29th, the flies issu- 

 ing September loth and I2th respectively. 



It is a pleasure to state that at least one of the flies 

 found in houses is probably beneficial rather than in- 

 jurious, and that this species is Scenopinus fenestralis. 



