WINDOW FLIES 217 



of this species as an enemy of M. dome.stica. Sometimes small 

 shining black flies belonging to the genus Scenopinu.s are found 

 in the windows of houses. They measure about one quarter of an 

 inch in length and have been called " window flies " by Comstock. 

 The larvae of these flies appear to be carnivorous in their habits. 



Many other flies accidentally stray into houses, but so far as 

 we have been able to ascertain by their feeding and breeding 

 habits, the species which have been considered are the only flies 

 which are of special economic interest. No general statement, 

 however, can be made, for in spite of the advance in our know- 

 ledge as to the economic relationships of the Diptera which has 

 taken place during the past few years, the information we now 

 have available only serves to indicate how little we really know 

 concerning this important order of insects. 



