8 THE CLASSIFICATION OF INSECTS 



ing to the views of the physico-philosophers, the Coleoptera, Neuroptera, Hymenop- 

 tera, Diptera, and Lepidoptera belong together, because they undergo extensive 

 changes in their metamorphoses. But I have already shown that, however exten- 

 sive these metamorphoses may be, they do not rise in any of these orders beyond 

 the development which the Lepidoptera attain in their pupa condition ; as in the 

 pupa of Lepidoptera the jaws are already transformed into a sucker-like proboscis, 

 when wings and legs are developed ; while Coleoptera, Orthoptera, and Hymenop- 

 tera have arrived at their mature condition before the jaws have reached a higher 

 development of structure than that which is exemplified in the metamorphoses of 

 Lepidoptera before they fully pass into the condition of their pupa. So that, not- 

 withstanding their extensive metamorphoses, the mandibulate insects must be 

 placed altogether below the haustellate, even below the Hemiptera ; and thus the 

 classification proposed at the outset seems fully justified by embryological evidence ; 

 and, if I am not mistaken, we shall in future consider Mandibulata as forming one 

 great natural division among insects, to be placed below the Haustellata. 



This conclusion furnishes another illustration of the fallacy of our reasoning, 

 when we allow ourselves to be guided simply by analogy derived from other classes. 

 If among the higher animals we had not a natural series passing from man, through 

 monkeys, to the carnivorous animals, I doubt very much whether we should ever 

 have been led to consider the muscular power and the strength of the jaws as 

 indicating anywhere a higher degree of organization. But this impression, which 

 is correct among Mammalia, can no longer obtain in other classes. We should, 

 on the contrary, be better advised, by this evidence, and in future derive our views, 

 as far as possible, solely from the classes to which they are to be applied. 



The same evidence which shows Lepidoptera to rank highest among Insects, 

 shows also that Insects as a class rank higher than Crustacea. And it will not be 

 out of place to remember here the happy suggestion of Oken, who says, that 

 " Lepidoptera are born as Worms, then pass into the condition of Crustacea, and 

 are finally developed into true Insects, exemplifying the natural order of gradation 

 of the three classes of Articulata." 



The detailed history of the metamorphoses of some Lepidoptera will sustain 

 more fully the views introduced in the preceding pages. 



II. THE METAMORPHOSES OF EUDAMUS TITYRUS. 



THERE is no order in the class of Insects the transformations of which have been 

 more extensively studied than those of Lepidoptera. The knowledge of their 

 earlier condition has been of late so much extended, that entomologists have even 

 derived many important characters for their classification from the investigations 

 of these earlier stages of growth. There are, however, several subjects of impor- 

 tance, in a physiological point of view, to which attention has not been sufficiently 

 directed. Though we know the different forms of the larva, of the pupa, and the 

 perfect insect, and though in most cases Lepidoptera may now be recognized in 

 either of these conditions, the manner in which the changes are brought about has 

 not been sufficiently examined. 



