SHEATH- WINGED INSECTS. 



363 



of rings, while others are provided with a complete horny or shell- 

 like case. 



Most insects have wings, and such undergo certain metamor- 

 phoses, or changes of form. Those which are unsupplied with 

 wings continue during life of the same form and structure as at 

 birth. They are all furnished with six legs, with the exception of 

 the millepedes, which always have more, and the number of which 

 also increases with their age. 



Linnasus forms seven orders of Insects, and his classification 

 is founded upon the presence or absence of wings, their number, 

 texture, arrangement and the nature of their surface, and also 

 upon the presence or absence of a sting. These orders are — I. 

 Coleoptera, or sheath-winged insects ; II. Hemiptera, or half-winged ; 

 III. Lepidoptera, or scale-winged ; IV. Neuroptera, or nerve- winged ; 

 V. Hymenoptera, or membrane-winged ; VI. Diptera, or two- 

 winged; and VII. Aptera, or wingless insects. 



I. — SHEATH-WIXGED INSECTS. 



In the Coleopterous Insects the upper pair of wings consists 

 of a crustaceous or horny sub- 

 stance ; and these cover or defend 

 thfi other pair, which, being of a 

 more soft and flexible texture, are 

 folded beneath them. This species 

 of insects is very numerous and well 

 known, and many of them are very 

 remarkable for the singularity of 

 their forms and the beauty of their 

 colors. It includes the beetles, 

 winged bugs, etc., all of which un- 

 dergo a complete metamorphosis, or 

 change of form. 



The Elephant Beetle is the 



largest of this kind hitherto known, 



and is found in South America, 



particularly Guiana and Surinam, 



80* X 



DigeBtivf Apparatus of tho Bi^L'tle 



