FROM EMBRYOLOGICAL DATA. 15 



which it is now presented to us has led to an extensive comparison between these 

 changes of the butterfly, and the permanent states and features of the different fam- 

 ilies of Insects ; and, from this comparison, the necessity of extensive changes in 

 the classification of Insects has been shown, and an entirely revised system, resting 

 upon these new views, has been proposed. 



There are now further consequences, following easily from the facts already men- 

 tioned, which remain to be traced to their full extent. We have shown the in- 

 fluence the knowledge of these metamorphoses must eventually have upon the 

 classification of Insects at large. We have now further to investigate the bearings 

 of these facts upon the special arrangement of Lepidoptera among themselves, and 

 also to trace out the analogies between those changes of the Lepidoptera and the 

 permanent characters of the other classes of Articulata. For it is not enough to 

 have shown that the classification of Insects has to be modified upon this evidence ; 

 we must investigate with equal thoroughness the importance of these facts Avith 

 reference to the relative position of the different classes which have been distin- 

 guished among Articulata in general, and also trace the immediate consequences of 

 a more complete knowledge of the transformations of Lepidoptera, as bearing upon 

 theu" special arrangement. 



Let us first examine the relations of these facts to the special classification of 

 Lepidoptera among themselves. This family, or order, of Insects is generally divided 

 into three natural groups, Diurnal, Crepuscular, and Nocturnal ; or Butterflies, 

 Hawk-moths, and Moths ; which divisions are by some reduced to two. Diurnal 

 and Nocturnal Lepidoptera, — the Sphinges being then considered simply as a fam- 

 ily among Moths, and not as a primary division in the whole order. The question 

 now arises, in what succession these families should be placed, whether we consider 

 the larger groups or the minor subdivisions. Of course, I do not feel prepared to 

 express a decided opinion upon every doubtful point in the classification of Lepi- 

 doptera, but simply inquire into the principle of their classification, and try to 

 obtain some light respecting their gradation, from the facts observed in Eudamus. 

 It is generally considered that diurnal Lepidoptera rank highest, and Sphinges are 

 invariably placed between Butterflies and Moths. I have, however, looked in vain, 

 in all the works upon Lepidoptera Avith which I am acquainted, for arguments 

 intended to justify and sustain this arrangement ; and though this order of succes- 

 sion is universally admitted, I do not find that it is anywhere expressly sustained, 

 or that allusion is anywhere made to the evidence that they ought to be considered 

 in that succession, and that this arrangement is intended to express the true relative 

 position of these families. It seems as if this arrangement had been introduced 

 simply for the sake of convenience, by common consent, without having resulted 

 from an inquiry into the subject ; or perhaps it has been adopted in consequence of 

 the more extensive knowledge early observers have had of the diurnal Lepidoptera, 

 and from the great difficulty in obtaining and studying the minor species among the 

 nocturnal ones. But whatever may be the cause of this arrangement, so much is 

 plain, that, as soon as the question is raised about its value, it will be found to 

 be still unsettled. I do not, however, oppose the present arrangement. On the 



