﻿HABITS AND STRUCTURE OF INSECTS. 93 



Opening, wliicli is represented in the figure ; and where the 

 abdomen joins the thorax, a cavity lined with a delicate skin 

 will be found, which is called the tijmpamcm^ and is supposed 

 to be an organ of hearing. If the softer parts within the 

 body of an insect be removed and slightly compressed be- 

 tween two pieces of thin glass, the air-tubes, looking like fine 

 white threads, may be seen with an ordinary pocket-lens. 



The air-tubes are called trachece, and the openings on tho 

 outside of the body which communicat3 with them are called 

 sj)iracles. 



87. Insects breathe by dilating and contracting the ab- 

 dominal segments. The act of breathing; can be plainly seen 

 in the grasshopper or the honey-bee, and it will be noticed 

 that after violent exercise, as in a long flight, the insect 

 breathes more rapidly than when it has been at rest for some 

 time, just as a boy after running finds himself compelled to 

 breathe rapidly for a while. 



After violent exercise the insect gets tired and rests. Bees 

 may often be seen, after a loi]g flight, to alight in the grass 

 near a flower, and for a w^hile appear so fatigued that they 

 cannot reach the flower, but remain breathing verj- rapidly. 

 Insects have curious ways of resting and sleeping. A species 

 of wasp has been observed soundly sleeping while holding on 

 to a blade of grass by its jaws alone, the fore-legs just touch- 

 ing the grass, while the body and the middle and hinder 

 pair of legs were hanging downward, and not bearing against 

 the grass at all, as sho^Ti in Fig. 91. 



88. In this connection it may be well to allude briefly to 



