INVERTEBRATA. 421 



the ether an object of absolute beauty, a form in which all 

 excesses of ornamentation seem perfected, and whose dainty 

 appetite can feed only upon the nectar of flowers. The 

 recitations of interesting and strange things in this depart- 

 ment would be endless. Reflect 1 Science has recognized 

 more than one hundred thousand insects ; patient natural- 

 ists have watched and worked, and the microscope has lifted 

 the veil of mystery from their private lives, organization, 

 and habits, and entomology stands one of the most exten- 

 sive and curious dominions of knowledge possessed by man. 

 Of the classification or manner in which this knowledge is 

 arranged, a number of systems have been adopted by dif- 

 ferent entomologists. The general observations of Heck on 

 the anatomical elements of the Articulata embrace, of course, 

 the structure of the insect. He says : " The Articulata are 

 named from having the various parts of the body and limbs 

 articulated to each other. The nervous system is composed 

 of ganglions united by a double cord, and there is usually a 

 kind of outside skeleton composed of a series of rings pro- 

 tecting the interior parts, and serving as points of attach- 

 ment for muscles. In some classes respiration is affected 

 by means of branchia3, and in others by tracheae, or air 

 tubes. When limbs are present, they are never fewer than 

 six." 



Cuvier, after an extended dissertation on the anatomy and 

 physiology of insects, remarks, on their classification : "All 

 general systems or methods, relative to insects, are reduced 

 essentially to three. Swammerdam based his on their me- 

 tamorphoses ; that of Linnaaus was founded on the presence 

 or absence of wings, their number, consistence, superposi- 

 tion, the nature of their surface, and on the deficiency or 

 presence of a sting. Fabricius had recourse to the parts of 

 the mouth alone. In all these arrangements the Crustacea 

 and Arachnides are placed among the Insects, and in that 

 of Linna3us, the one generally adopted, they are even the 

 last. " He then proceeds with his own classification : 



36 



