FLIES FOUND IN HOUSES 



IS 



flies are the same size as old flies. Occasionally flies are met 

 with which are smaller than the normal individuals of the species. 

 This is usually due to insufficient or unsuitable food during the 

 larval stage. Hermes experimentally investigated this question 

 and one of his plates is reproduced showing the effect of starva- 

 tion and of overfeeding during the larval periods 



Classification of Jionse-freqiienting flies. 



In the following pages the adult forms, larvae, life-histories, 

 habits and distribution of the common house-frequenting non- 

 biting flies will be very briefly described, but for the sake of 

 reference their zoological classification is briefly given in the 

 following table, the families and species being arranged in the 

 apparent order of their hygienic importance. 



Order Diptera. 

 Sub-order Cyclorrhapha. 



Sub-order Orthorrhapha. 



Psychodidce Psychoda sp. Moth fly or Owl midge 



Scenopinidce Scenopimts feuestralis Window fly 



* Stomoxys calcitrans is a blood-sucking fly and is included in this list because it 

 is so often mistaken for the house-fly. 



' It must be clearly understood that the foregoing account refers only to the muscid 

 house- frequenting flies. For the life-histories of other dipterous insects the reader is 

 referred to text-books on general entomology. 



