98 INSECTS. 



books. The athletic powers of a few insects, the student 

 has had an opportunity to test for himself. When size is 

 taken into account, it is probable that the champion ath- 

 letes of the world will be found to be insects, at least in 

 running, jumping, and flying. 



IV. Sensation. The nervous system consists of a 

 double chain of ganglia, extended lengthwise on the 

 floor of .the body cavity, and connected anteriorly with 

 a large cerebral ganglion in the head by a nerve each 

 side of the gullet. From the cephalic ganglion or brain, 

 nerves go to the eyes and other parts of the head, while 

 each segment of the body is supplied with nerve fibers 

 from a subjacent ganglion. 



The five senses known to us are probably possessed by 

 all insects. The sense of touch, while common to most 

 parts of the body, is somewhat specialized in antennse, 

 palpi, and various tactile hairs. Organs of sight have 

 reached a wonderful development in the compound eyes. 

 We have no means of knowing what may be the limits of 

 the power of vision in such organs. The sense of smell 

 (or some other to us unknown sense) is undoubtedly 

 present, enabling insects to find hidden food. Certain 

 microscopic structures in the antennse are believed to be 

 organs of smell. No undoubted organs of hearing are 

 yet known; but it is probable that insects can hear, for 

 many of them possess elaborate sound-producing appara- 

 tus. Supposed organs of taste have been found in the 

 labium and lower side of maxillae. 



The instincts 1 of insects are the subject of many books. 

 They are shown in manifold ways, and in no two species 

 of insects in precisely the same way. They are too 

 diverse to admit of summarizing here. But the instincts 



1 "An instinct is a propensity prior to experience, and independent of 

 instruction." PA LEY. 



