46 AN INTRODUCTION TO ENTOMOLOGY. 



many of them are entitled to this rank. In the following pages 

 most of these families are discussed under the head of the. orders in 

 which they have been most commonly placed ; in each case, how- 

 ever, the possible rank of the group as a distinct order is indicated. 



There is one more proposed modification of the Linnaean system 

 which should be noticed in this place. Nearly all of the families in 

 the orders Pseudoneuroptera and Neuroptera are remarkably dis- 

 tinct. Each family differs from the other families in the same order 

 in much more important characters than usually distinguish families 

 in the other orders. At the same time the characters which distin- 

 guish either of these orders are not well marked. For these reasons 

 Professor Brauer holds that the Pseudoneuroptera and the Neurop- 

 tera are not natural orders, but that the former group includes four 

 and the latter three distinct orders. 



Although in some respects (as, for example, in the classing to- 

 gether of the Termitidae, Psocidae, and Mallophaga as an order, the 

 Corrodentia) I cannot follow Professor Brauer, I am inclined to think 

 that in the main the school of entomologists which he represents is in 

 the right as regards the number and characters of the orders of the 

 Hexapoda. And I frankly confess that in adhering so closely to 

 the old classification I have been greatly influenced by a desire to 

 make my presentation of the subject as simple as possible, and by 

 the belief that an elementary text-book should follow rather than 

 lead in matters of this kind. I have, however, endeavored to pre- 

 sent the facts in such a manner as to clearly indicate the ideas of 

 the different schools. 



On the following page two lists of orders are given. In the first 

 column are indicated the orders recognized in this work ; in the sec- 

 ond column are indicated the various other orders that have been 

 proposed. The reasons in each case for considering these smaller 

 o-roups orders is given later, under the special discussion of the 

 group. 



LISTS OF ORDERS OF HEXAPODA. 



I. II. 



I. Thysanura. Thysanura. 



f Plectoptera. {Ephemeridcz^ 

 I Odonata. {Libellulidcei) 

 II. Pseudoneuroptera. - Plecoptera. (Perlida:) 



Corrodentia. {Mallophaga, Psocidce, Ter- 

 [ nu 7 U'du-.) 



