246 Caterpillar Hoiisc Fly. 



63. When about six weeks old it stops eating, and 

 covers itself with a kind of cobweb or cocoon, which it 

 fastens to a convenient branch. There it hangs as a 

 chrysalis, until it bursts the case and sails into the air on 

 beautifully colored wings to spend the rest of its short life 

 in flitting among flowers and blossoms and sipping honey. 



64. The microscope shows that the wings of the But- 

 terfly are covered with numberless little scales of every 

 variety of form and color, and that its eyes are composed 

 of a great many smaller eyes. 



65. Butterflies generally live but one season, 

 although some live through the winter. 



66. The HOUSE FLY has two wings, six legs, 

 a sucking proboscis for taking its food, and two 

 great eyes which are composed of 4,000 small 

 eyes. 



67. Its feet are remarkably formed to enable it to 

 creep up smooth surfaces like glass or on ceilings. 



68. It holds on by means of a gum or sticky substance 

 with which its feet are supplied ; some say it holds on by 

 means of sharp little hooks on the feet ; and others say its 

 feet, when pressed against glass or the ceiling, form vacu- 

 ums, and that the fly is held on by the pressure of the air 

 (as explained on page 74). 



69. Most Flies die when frost comes; but some of 

 those which hide away in warm nooks and corners live 

 just long enough to lay a great many eggs the next sum- 

 mer. In a few hours these eggs are hatched into little 

 grubs which, in a few days, become flies. 



