31 



The sub-class Insecta, or true hexapod insects, is the highest in this 

 series. It divides into orders, as follows: 

 I. Those in which metamorphosis is distinct : 



1. Pupa inactive : 



Orders : Hymenoptera, Colcoptera, Lcpidoptera, Diptera. 



2. Pupa active : 



Orders : Hemiptera, Orthoptera. 



3. Pupa variable : 



Order : Neuroptera. 

 II. Those which do not undergo metamorphosis : 

 Orders: Arioplura, Thysanura. 



The order given here is considered as descending, but the arrangement 

 of the series is by no means a settled question with entomologists. I prefer 

 » that of Dr. Packard, given in his " Guide to the Study of Insects," to any 

 other which I have seen. This system, starting with the Neuroptera as the 

 lowest in the scale, ascends in two branches — one through the Diptera and 

 Lepidoptera to the Hymenoptera; the other through the Orthoptera and 

 Hemiptera to the Coleoptera, the latter branch not reaching quite as high a 

 point as the other. He places the Orthoptera, not directly above the Neu- 

 roptera, but sub-parallel to that order. 



Illustrating the positions and relations of these various groups by the 

 idea of development of the higher from the lower, and omitting the interme- 

 diate steps, we would consider the Orthoptera as arising from the Crustacea, 

 the intermediate non-metamorphosing groups — Anoplura and Thysanura — as 

 representing those which had been retarded, and as connecting more directly 

 with the Neuroptera. Following out this idea, I would, as a matter of course, 

 so arrange the various families of Orthoptera as to bring those which approach 

 nearest to the Crustacean form to the foot of the series, excej^t so far as 

 necessarily modified by organization and development. And this brings us 

 again to the consideration of the arrangement of the various families of the 

 order. 



Linnaeus,* in the later editions of his " Systema Naturae," separates the 

 Forficula from the rest of the Orthoptera, and unites them with the Coleoptera 

 as its last genus. The rest of the order he places under Hemiptera, thus : 



* For !X more coinplete statement of the arrangement by Linna?uR, see Mr. Scnd- 

 der's iiaper on the " Arrangement of the famihes of Orthoi)tera," Proc. Bost. Soc. Nat. 

 Hist., XH (1SC9), 228. 



