44 THE HOUSE FLY DISEASE CARRIER 



idea that the species constantly hibernates in this con- 

 dition. Upon the emergence of the adults which he 

 reared in confinement in February, they were trans- 

 ferred to a large net cage and were kept alive success- 

 fully for eleven and one-half weeks. The original flies 

 caught in the kitchens in February were kept in cap- 

 tivity for ten weeks. How long they had lived before 

 capture, of course, was unknown, but presumably since 

 the previous autumn. The question of the length of 

 life of the adult fly under all conditions will be con- 

 sidered in a later paragraph. 



HABITS OF THE ADULT FLY 



On issuing from its pupal sheath, the first impulse 

 of the adult fly is to feed. After its rest in the pupal 

 condition, during which time it has taken no food and 

 has subsisted by the physiological consumption of the 

 fat cells stored up during the last larval period, it has 

 naturally become hungry, and it flies immediately to the 

 first point offering sustenance. The sense of smell of 

 the typhoid fly must be very keen, although its selec- 

 tion of attractive odors undoubtedly differs from our 

 own. It is very catholic in its choice of food the milk 

 jug and the freshly baked custard pie are apparently 

 equally in favor with the slop bucket, the garbage pan, 

 and all sorts of unmentionable filth. It knows the odor 

 of cooking, and it flies unerringly towards the nearest 

 kitchen, although here the temperature of the kitchen 

 stove may attract it almost as much as the possibility 

 of something good to eat. As has been shown in our 



