THE ORDERS OF THE HEXAPODA. 45 



opinion is in regard to the order Neuroptera. In this order as de- 

 fined by Linnaeus there are included insects with a complete meta- 

 morphosis as well as those with an incomplete one. So radical a 

 difference as this can hardly be expected to occur within the limits 

 of the same order.* For this reason those families in which the 

 transformation is an incomplete one were separated by Erichson as 

 the order Pseudoneuroptera ; and the term Neuroptera restricted to 

 those in which the metamorphosis is complete. This adds one to 

 the list of orders. In the following pages I have considered the 

 order Pseudoneuroptera, as distinct from the order Neuroptera. 



Gerstaeker and some others of the German entomologists do not 

 stop with the separation of the Pseudoneuroptera from the Neurop- 

 tera. They hold that there is no important character separating the 

 former order from the Orthoptera ; and they therefore include in the 

 order Orthoptera not only the insects commonly placed there by the 

 English and American entomologists, but also those of the Linnaean 

 order Neuroptera in which the metamorphosis is an incomplete one. 



We have, therefore, three slightly differing systems, which agree 

 as to the orders Hemiptera, Lepidoptera, Diptera, Coleoptera, and 

 Hymenoptera, but differ as to the other orders. These differences 

 are represented in the following table. It will be noted that al- 

 though the classification of Olivier and that of Gerstaeker present 

 the same names, these are used with widely different signification. 

 The Orthoptera of Gerstaeker includes much more, and the Neurop- 

 tera much less than in the classification of Olivier. 



OLIVIER. ERICHSON. GERSTAEKER. 



Orthoptera. Orthoptera. } 



Orthoptera. 



C Pseudoneuroptera. } 

 Neuroptera. 



( Neuroptera. Neuroptera. 



Although the Linnaean system slightly -modified in one or another 

 of the three ways just indicated is still very generally accepted, 

 there are many entomologists who hold that further modifications 

 should be made. There are certain families, as the Earwigs, Fleas, 

 Thrips, and others, each of which differs greatly from the typical 

 representatives of the order in which it was at first placed. Each 

 of these families have in turn been raised to the rank of an order. 

 But there is as yet little agreement among systematists as to how 



* The males of the Coccids are the only insects which present an exception in this 

 respect. 

 4 



