1 86 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



of which arise a fine tapering hair, into which runs a 

 nerve fiber. The vibrations of the air reverberated in the 

 hollow determines corresponding vibrations of the hair 

 and affect the nerve. 



This style of hearing organ reaches its highest per- 

 fection in the mosquito, especially in the male mosquito.* 



Fig. 119. — Head of a mosquito. The two lower and longer antenna? are 

 feelers, the two upper ones with radiating hairs are auditory. (After 

 Mayer. ) 



Fig. 119 represents the head of the male mosquito with 

 its compound eyes and auditory organs. There are two 

 kinds of antennae : the one (the lower in the figure) are 

 feelers or organs of touch, the other (the upper) are 

 organs of hearing. As in the spider, these come from 

 the bottom of hollow cups, which probably act as resona- 

 tors, increasing the air vibrations; and the long hair- 

 like, many-branching antennae respond by co-vibrations. 

 A nerve runs up each antenna and sends a fiber to every 

 branch. Surely this is an admirable arrangement for 

 responding to aerial vibrations. 



But, according to the investigations of Mayer and 



* Mayer, Am. Jour., viii, 81, 1874 ; Arch, des Sci., li, 263, 1874. 



