178 INTERNAL ANATOMY OF INSECTS. 



der this head I may also observe, that the muscles are 

 sometimes extremely slender threads, crossing each 

 other, and often curiously interwoven in various direc- 

 tions, so as to resemble lace or fine gauze, as may be 

 seen in the alimentary canal of some caterpillars 3 ; some- 

 times also they surround part of this organ, like a series 

 of minute rings b . 



iv. Colour. The most usual colour of the muscles of 

 insects is white : those for flight however, according to 

 Chabrier, differ from the rest, by being of a deeper and 

 reddish colour ; and I have observed likewise that those 

 in the head of the stag-beetle, when dried at least, are 

 red, and look something like the flesh of warm-blooded 

 animals. 



v. Kinds and Denomination. In general, muscles 

 may be regarded as divided into primary and secondary 

 tine primary being the muscles by which the principal 

 movements of any organs are effected, and the second- 

 ary their auxiliaries which are the cause of subordinate 

 movements d . Every muscle almost has its antagonist, 

 the action of which is in an opposite direction ; so that 

 when it is equal, the organ to which they are attached 

 remains without motion ; but when that of one prepon- 

 derates, a movement in proportion takes place e . The 

 principal antagonist muscles that may be found in insects 

 are the following. 1. Levator muscles that raise an or- 

 gan, and Depressors that depress it. 2. Flexors that 

 bend an organ, and Extensors that unbend or extend it. 



* Lyonet Anat. t. xiii./. 1, 2. 



> Ramdohr Anat. t. v./. 1. e.f. 3. 



c Chabr. ubi supr. 440. d Ibid. 44,2, &c. 



N. Diet. d'Hist. Nat. xxii. 80. 



