FIFTH ANNUAL REPORT 



CLASSIFICATION. 



This subject may be disposed of in few words, though we can not 

 speak intelligently of insects, without some idea — however general — 

 of their relations. In treating a subject about which so much has 

 been written, the study should be what not to say, rather than what 

 to say. All insects, as just defined, are referable to one or the other 

 of seven well-defined Orders, founded on the structure of the mouth 

 in the imago, the number and nature of the wings and the transforma- 

 tions. Some of these Orders are, however, connected by aberrant and 

 osculant families, or groups, which have, by certain authors, been 

 ranked as independent Orders ; but which it will be more convenient 

 — if not more natural — to consider Suborders. In my lectures I have 

 found it very convenient to make use of the following pyramid, (Fig. 

 1), which gives at a glance the distinguishing characters and the rela- 

 tive rank of these seven Orders and of the osculant groups : 



[Fig. 1.] 

 HTMENOPTERA, Linn. 



COLEOPTEEA, Aristotle./ 1 



/ ' 

 tera, Kirby./^ 



ORTHOPTERA, OUv.j<, 

 Euplexopterd, West. 

 Trichoptera , Kirby 

 NEUROPTERA, Linn./.5 

 Dictyotoptera, Burm 

 Th,ysanoj)tera , Haliday 



LEPIDOPTERA, Linn. 



^iJlHEittlPTERA, Linn. 



■^Xllomoptera, MacLcay. 

 >?\DIPTERA, Aristotle. 

 % \ Apli aniptera , Kirby. 



= Order. O = Sub-order. 



Pyram;d showing the nature of the mouth, and relative rank of the 

 Orders, and the affinities of the Sub-orders of Insects. 



Scenopinus, and , as explained by Packard himself, (Guide, p . 401) , remarkable for the double-segmented 

 appearance of all the abdominal joints, except the last one, so that the body appears to have 21 instead 

 of 13 joints. As to the different classiflcations, authors have differed in the past and will differ in the 

 future, as to what constitutes a natural sysiem; and to attempt to harmonize or even consider the 

 various plans would be to discu.ss words and not things. Remembering that classifications are but 

 means to an end— appliances to facilitate our thought and study ; and tliat, to jiise Spencer's words, 

 "we can not by any logical dichotomies, accurately express relations which in nature graduate into 

 each other insensibly, " the difference of opinion becomes intelligible; and for my part I adopt that 

 system which appears most natural, and which best promotes the object in view. It is essentially that 

 *)f Westwood, given in his "Introduction," which has justly been called tlie entomologist's bible. Those 

 Avho include the Araclinida and Myriapoda in" the same Class with Insects, must particularize the latter 



