INSECTS, 



which live in water have on the sides of their body filaments or 

 appendages in the form of laminae, upon which are spread vessels 

 communicating with the bronchi and tracheae. 



Though Insects have no lungs, and are destitute of voice pro- 

 perly so called, yet they possess the means of producing sounds. 

 Thus the male grasshopper makes a noise to attract the female. 

 The males of the Cicadae and the Crickets possess the same 

 faculty. In all these insects, however, the means by which 

 the sound is produced is similar to that by which a stringed 

 instrument or a drum is sounded. The males of the locusts 

 and grasshoppers have a portion of the internal margin of 

 their elytra formed of an elastic transparent membrane, like 

 talc, provided with strong projecting ribs, separated by large 

 hollow spaces. It is a kind of violin, of which the ribs repre- 

 sent the strings ; and the sharp disagreeable sound by which 

 these insects are distinguished at a distance is produced by 

 rubbing the elytra over one another. In the cricket, the thigh, 

 furnished with projecting lines, serves as the bow, and the longi- 

 tudinal ribs of the elytra the strings. In the Cicadae the organ 

 which produces the sound is more complicated. It is a species 

 of drum, and is peculiar to the male. The abdomen, which is 

 conical, is provided below and near the base with two large semicir- 

 cular scales, which cover an empty space, in which is a delicate 

 tense membrane equivalent to the skin of the drum ; and below 

 this membrane, at the bottom of the cavity, are other parts 

 which, striking against it, produce the sound. The stridulous 

 noise which is heard when the Sphinx atropos is touched, is oc- 

 casioned by the air escaping rapidly by a trachea at the sides 

 of the base of the abdomen, and which is closed in the state of 

 repose by a bundle of stellated hairs. Many Coleoptera pro- 

 duce a plaintive and interrupted sound by rubbing the peduncle 

 of the base of the abdomen against the interior walls of the 

 thorax ; and the extremity of the head in others produces a simi- 

 lar sound. The rapid vibration of the wings is the chief cause 

 of the humming noise which most insects produce when flying. 



Insects feed on all kinds of matters, vegetable and animal ; and 

 there is scarcely any production in these two divisions of Nature 

 which does not serve as the food of some insect. Each insect, 

 besides, has a particular food upon which it lives in preference, 



and which it is endowed with the power of discovering andprocur- 



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