INTRODUCTION. IX 



Pupa active ; wings 4 ; prothorax free ; 



Month mandibulate. VI. Orthoptera. 



Mouth haustellate. VII. Hemiptera. 



§ § Metamorphosis none ; wings wanting ; 



Abdomen without appendages. IX. Anoplura. 



Abdomen with anal appendages. X. Thysanoura. 



The order Neuroptera is very difficult to define, though the 

 sub-orders composing it are very readily distinguished from any 

 of the other orders. 



Several so-called orders will by this scheme become attached 

 to the orders here recognized, by possessing a majority of the 

 characters above mentioned ; thus the Strepsiptera become the 

 Coleopterous family Stylopidae ; the Thysanoptera and Euplex- 

 optera unite with the Orthoptera ; the Aphaniptera with the 

 Diptera, and the Trichoptera become a sub-order of Neuroptera. 



Having thus exhibited the elementary characters upon which 

 the orders are based, the special subject of the present treatise 

 may now occupy the attention of the student. 



In order that the body of the work may be made intelligible to 

 the beginner, it will be necessary to make a brief exposition of 

 the external anatomy of Coleopterous insects, before attempting 

 to define the numerous families which compose the order. The 

 three regions, the head, thorax, and abdomen, will therefore be 

 taken up in succession. 



HEAD. 



The anterior portion of the body is called the head ; it varies 

 greatly in form, and is joined by membrane to the thorax. Usually 

 the hind portion is but slightly narrowed, and enters the anterior 

 part of the thorax ; sometimes the part behind the eyes is sud- 

 denly narrowed, and constricted, forming the neck. 



The surface of the head consists of a solid horny plate ; above 

 it is frecpiently marked by a single suture, running transversely 

 between or in front of the antennae ; this is called the clypeal or 

 frontal suture. The portion in front of this suture, when dilated 

 so as to project over the mouth, as in many Scaraboeidae, is called 

 the clypeus; when small, it is named epistoma, and is sometimes 



Orthoptera being terrestrial, and using their wings only as accessaries in 

 progression, while the Pseudoneuroptera are essentially aerial, passing the 

 greater portion of the time on the wing. 



