OF INSECTS. 193 



It is evident that their apparatus of muscles, on which 

 ill these acts depend, must be at once ample and 

 powerful. Although Lyonnet's enumeration of the 

 nuscles of the cossus has heen often cited, we are 

 Acquainted with no other instance which so well ex- 

 ismplifies their wonderful multiplicity. In that cater- 

 pillar he discovered no fewer than 4061, of which 

 228 belong to the head, 1647 to the body, and 

 |21 86 to the intestines, a number exceeding by 3532, 

 the amount of those which are to be found in the 



[human frame ! 



In some respects the muscles of insects have a 

 strong similarity to those of the vertebrata, but in 

 others a notable discrepancy is observable. For the 

 most part they consist of two portions, viz. the tendon 

 and the muscle. The muscle properly so called, is 

 formed of a multitude of straight fibres, and enveloped, 

 according to Lyonnet, in a membrane composed of 

 many parallel bands, consisting of bundles of fibres 

 enclosed in separate membranes. At one extremity 

 they are attached to the inside of the external crust, 

 and the various processes connected therewith, at the 

 other to the organ on which they are designed to 

 operate, their attachment being either immediate or 

 by means of a tendon. When the muscles are not 

 provided with tendons, the shape is determined by 

 that of the parts to which they are attached, and they 

 are commonly cylindrical or prismatic, retaining their 

 sides parallel throughout their whole course. Those 

 which are furnished with tendons are more variable 

 in form, and have been divided into several classes 



