SEPTENARY SYSTEM. 241 



able length : in these it has been my wish clearly to explain 

 the principal differences that are to be found among insects in 

 the structure of the segments, and the mouth, and in the stages 

 of metamorphosis. I would not be guilty of the impertinence 

 of referring to my own works, but that they really form a part 

 of my subject, and, united, constitute the source from which my 

 present observations are drawn. Moreover, the three chapters 

 in question are to be found in the prior pages of this Magazine, 

 and may fairly be considered introductory to the present inquiry. 

 The chapters are these — '* Art. XLVI. Osteology, or External 

 Anatomy of Insects." Ent. Mag. Vol. I. p. 394. " Art. VI." 

 on the same subject. Ent. Mag. Vol. II. p. 60. " Art. II. 

 A few words on the Transformation of Insects." Ent. Mag. 

 Vol. III. p. 12. 



In the first of these chapters I have detailed the principal 

 differences occurring in the segments of which every insect is 

 composed, both as regards bulk and form ; particular stress being 

 laid on the differences of those segments which bear the imple- 

 ments of locomotion, and on those differences which exist in 

 the structure and design of such implements. On these differ- 

 ences is founded the Alary System. In the second chapter 

 the differences occurring in the mouth have been carefully 

 described, and this not solely with a view to their subsequent 

 employment as the support of a theory, but also with a design to 

 introduce a uniform anatomical nomenclature of the various com- 

 ponent parts. On the differences in the mouth is founded the 

 Maxillary System. In the third chapter the different modes 

 of transformation are described and compared. On these 

 differences is founded the Metamorphotic System. The facts 

 detailed in these chapters have, without exception, (as far as I 

 recollect at the present moment,) passed under my own obser- 

 vation, and are not dependent, in any degree, on the assertions 

 of others. This I mention, because facts so stated should be 

 subject to contradiction only from those who can speak from 

 observation, and should not be disputed because previous 

 writers may have stated them differently. And here I may 

 further state, that the inquiry was, in every instance, made 

 with perfect fairness, and a fixed determination to abandon 

 such parts of my proposed system as would not harmonize 

 with these three great and indisputable systems. So far from 

 avoiding the application of any other extensive series of diffei'- 



