49 [ 469 ] 



tions, more by tlieir odor tlian l)y tlieir visible characters. But no organ 

 of smelling has been discovered, and this sense is supposed, from anal- 

 ogy, to be located in tlie lining membrane of the spiracles. 



Taste and ToucJi. — It is impossible to determine, but there is no rea- 

 son to doubt, that insects, like other animals, taste and enjoy the food 

 of which they partake ; and the manner in which they frequently touch 

 their food and the surfaces over which they walk, ^Aith the tips of their 

 palpi, which, indeed, have received the common name of feelers, renders 

 it probable that these organs are endowed with a special sense of touch. 



SOUNDS PRODUCED BY INSECTS. 



The songs of birds, and the noises made by other animals, are pro- 

 duced by the forcible passage of air through the glottis, which is the 

 narrow opening at the top of the wind-pipe, aided by the vibration of 

 certain muscular folds near the outlet, called the vocal chords. But we 

 have seen that insects never breathe through their mouths, and there- 

 fore they never make any oral sounds. But the humming of bees and 

 flies is produced m an analogous manner, by the expulsion of air through 

 the thoracic spiracles, and the \'ibration of a delicate valve-like fold, 

 just within the opening. 



But besides this, insects make a variety of noises, which are produced 

 in different ways. The singing of the Cicada, which is tbe loudest noise 

 made by any insect, is produced by the expulsion of air from the fli'st 

 abdominal spiracle, striking upon a large transparent drum-like appa- 

 ratus, situated at the base of the abdomen. The chirping of crickets is 

 produced by rubbing together their parchment-Uke wing-covers. The 

 well known noise of the katy-did is produced in the same way, but here 

 the sound is intensified by a thin talc-like plate set into the base of each 

 wing-cover. The stridulation of grass-hoppers is caused by the friction 

 of their spined shanks across the edge of their wing-covers. The 

 fainter, squeaking sounds, made by many insects when captured, are 

 produced simply by the rapid friction of one part of their bodies upon 

 another; in certain Hemiptera, by the friction of the head upon the pro- 

 thorax ; in the Cai^ricorn beetles, by the friction of the j)ro-thorax upon 

 the meso-thorax ; and in some of the Lamellicorn beetles, by the friction 

 of the abdomen against the wing-covers. 



The more complex and sjiecial apparatuses of insects for the production 

 of sounds, are possessed exclusively by the males, and are supposed to be 

 exercised by them as calls to the opposite sex, but the simpler squeaking 

 sounds are emitted by both sexes, and appear to be mere notes of 

 alarm. 



Vol. lY— 50 



