PARTS OP AN INSECT. 59 



tached to the under side of the thorax, while the wings 

 are attached to the upper side thereof. 



thorax. T J 



abdomen. > 1 



Fig. 59. — Head, having moutli-parts, anteimffi, compound eyes, 0; and simple eyes, a 



Thorax, having legs and wings. 



Abdomen, neyer having legs or wings, but having certain appendages at the extremity. 



5T. The wings of insects are never more than four in 

 number, and these are arranged in two pairs. 



The group of insects to which the house-fly belongs has 

 but two wings, or a single pair, and among this group (and 

 other groups of insects as well) there are some which have 

 no wings. 



The wings are very different in shape and structure in 

 distinct kinds of insects. In the common fly they are " 

 quite small, and transparent. In the butterflies they are 

 large and broad, and are covered with minute scales which 

 rub off on the fingers like dust. In the dragon-fly the 

 wings are long and narrow. 



