INSECTA. 331 



parts of the mouth alone. In all these arrangements the Crustacea and 

 Arachnides are placed among the Insects, and in that of Linnaeus, the 

 one generally adopted, they are even the last. 



I divide this class into twelve orders: the three first of which are 

 composed of apterous Insects, undergoing no essential change of form or 

 habits, merely subject to simple changes of tegument, or to a kind of a 

 metamorphosis, which increases the number of legs, and that of the 

 annuli of the body. The organ of sight in these animals is usually 

 a mere assemblage, more or less considerable, of ocelli resembling 

 granules. 



Certain English naturalists have formed new orders, based upon the 

 wings ; I see no necessity, however, for admitting them, that of the 

 Strepsiptera excepted, the name of which appears to me to be erro- 

 neous *, and which I will call Rhipiptera -f-. 



In the first order of the MYRIAPODA, there are more than six feet 

 twenty-four and upwards arranged along the whole length of the 

 body, on a suite of annuli, each of which bears one or two pairs, and of 

 which the first, and in several instances even the second, seem to form 

 a part of the mouth. They are apterous J. 



In the second or the THYSANOURA, there are six legs, and the abdo- 

 men is furnished on its sides with moveable parts, in the form of false 

 feet, or terminated by appendages fitted for leaping. 



In the third or the PARASITA, we find six legs, no wings, and no other 

 organs of sight than ocelli ; the mouth, in a great measure, is internal, 

 and consists of a snout containing a retractile sucker, or in a slit 

 between two lips, with two hooked mandibles. 



In the fourth or the SUCTORIA, there are six legs, but no wings ; the 

 mouth is composed of a sucker inclosed in a cylindrical sheath, formed 

 of two articulated portions. 



In the fifth or the COLEOPTERA, there are six legs, and four wings, 

 the two superior of which have the form of cases, and mandibles and 

 maxillae for mastication : the inferior wings are simply folded crosswise, 

 and the cases, always horizontal, are crustaceous. They experience a 

 complete metamorphosis. 



In the sixth or the ORTHOPTERA, there are six legs ; four wings, 

 the two superior in the form of cases, and mandibles and jaws for 

 mastication, covered at the extremity by a galea ; the inferior wings 



* Twisted wings. The parts taken for elytra are not so. See this order, 

 f Wings folded like a fan. + Destitute of wings and scutellum. 



