424 GEOLOGICAL SUEVEY OF THE TEEEITOEIES. 



I take great pleasure in acknowledging tlie many favors received from 

 the Smithsonian Institution, and return thanks therefor, and also to 

 Professor Baird and Dr. Gill for the valuable suggestions made in regard 

 to my work. 



II.— INTEODUCTOEY EEMAEKS. 



My study of the OrtJwptera has not been sufficiently extended and 

 thorough to enable me to form an arrangement of the various divisions 

 and subdivisions that is wholly satisfactory to myself. Yet it is proper 

 that I should at least indicate that system which I prefer, as it must to 

 a greater or less degree determine the characters selected to distinguish 

 the different groups, and the comparative value I attach to them. 



Therefore, without attempting at this time to discuss fully the reasons 

 therefor, I will state the order in which I believe the larger divisions 

 should be arranged, and the leading principles upon which it is based. 



Holding, as I do, the Cuvierian idea of four distinct types in the animal 

 kingdom, as explained and unfolded by Agassiz, it is unnecessary for 

 me to look further than the Articulata for the primary basis of an 

 arrangement of a single order of insects. Within the limits of this 

 group or "branch" are to be found all grades of development of the 

 type, from its lowest and most obscure to its highest form, from the 

 germ to the perfect animal. But the relations of the divisions of this 

 group — that is, of the Annelides, Crustaceans, and Insects — to each other, 

 must, to a certain extent, determine the arrangement of the divisions 

 of these classes. The principles and reasons that cause us to place the 

 Insects above the Crustaceans in the scale of being must, so far as they 

 can be followed out, determine the position of the various divisions and 

 subdivisions of the Insects in regard to each other. 



While I cannot wholly agree with Dr. Packard as to the value he 

 attaches to the different divisions of the Articulata, yet I prefer his 

 arrangement of the orders* of the Hexapod Insects to any I have seen. 

 This system, starting with JSfeuroptera as the lowest in the scale, ascends 

 in two branches, one through the Diptera and Lepidoptera to the Hyme- 

 noptera as the highest in the clavssj the other through the OrtJwptera 

 and Hemiptera to the Coleopteror, but this last branch does not reach 

 as high a point as that attained by the other. He places the OrtJwptera 

 not directly above the Neuroptera but sub-parallel to it. I believe that 

 this arrangement gives the true position to the OrtJioptera, for while this 

 order, as a whole, stands higher than the other yet it is not absolutely 

 above it. In other words, if I were an advocate of the Darwinian 

 theory of the development of genera and species from lower forms, I 

 would certainly hold that the OrtJwptera were not developed from the 

 Neuroptera, but that both orders arose from the Myriapoda, Crustacea, ov 

 some form of being lower than that found in the Hexapod Insects. 



Although I am not a disciple of this great naturalist, yet I believe we 

 may make use of the idea of development, which was advanced as early 

 as the time of Lamark, to assist us in fixing the position of the various 

 groups in the scale of being. As the highest form of a given type, (one 

 of the four grand divisions of the animal kingdom,) in its i)assage from 

 the germ ro the adult state, assumes for a time the lower leading forms 

 of that type, it follows that the various groups within that type stand 

 exactly in the same relation to each other that they would if the higher 



* I follow most entomologists, applying the name Order to the group he calls Sub- 

 order, and Sub-class to the division he calls Order. See his Guide to the Study of 

 Insects. 



