36 LIFE AND HABITS OF DOMESTIC FLIES 



sight without doubt, and yet it will brave its obvious 

 dangers to itself by persistently returning to one's nose 

 time after time. But however acute the senses of sight 

 and smell may be in the house-fly, both are almost 

 completely under subjection during the night-hours. 

 The nocturnal mosquito, on the other hand, is very 

 wide awake. A fly will sleep on the edge of a jam-jar 

 throughout the night even in the presence of a strong 

 light. Yet it possesses no eyelids its sleep must be 

 very profound. With the early dawn, however, the fly 

 is up and about. Its habits are the reverse of those of 

 the mosquito, although its eyes are apparently similar to 

 those of the blood-sucking insect. In a bedroom the 

 house-fly is the most annoying insect imaginable. The 

 detestable way in which it alights again and again on 

 the sleeper's face to drink the perspiration, its irritating 

 persistence, its hateful touch and the softness thereof, 

 combined with the knowledge of its life and habits 

 makes it the most loathsome of creatures. Watch the 

 fly being born on the manure-heap. Then observe it 

 on the edge of the milk-jug. Look at its track on the 

 window-pane or on a sheet of clean paper. Examine its 

 legs with a magnifying-glass and then watch it drown in 

 a cup of hot tea. Lastly, observe the flies swarming 

 over a ham in a restaurant or settling on the sugar- 

 basin. Ugh ! when we know what they do it is horrid. 

 The length of a fly's life also varies with the atmo- 

 spheric temperature. In very hot summers many of 

 the house-flies die when the weather becomes very 

 dry and oppressive. But when the temperature is 

 moderate the fly's life is prolonged as it is during the 

 larval stages. In the hottest English summers the 

 fly's life is believed to be about three weeks only, 

 but some observers have kept individual flies alive 



