74 NATURAL ARRANGEMENT OF INSECTS 



pose, for instance, we take the iuliform butterflies, the 

 most perfect of the diurnal Lepidoptera; now, although 

 the types of this division perfectly agree with our de- 

 finition, we nevertheless discover, as we proceed to the 

 aberrant examples, that Nature so modifies them, that 

 some assume the aspect and character of scolopendriform 

 larvfe, others have the thysanuriform shape, and so on. 

 So that, although the butterflies which stand at the head 

 of the iuliform division, as being typical, have iuliform 

 larvffi, yet that the group, taken as a whole, will contain 

 analogical representations of all the other types of larvae 

 we have described. The scolopendriform butterflies 

 {^Nymphalides Sw.), in the very same manner, contain 

 representations of iuliform, thysanuriform, vermiform, 

 and anopluriform caterpillars, besides their own proper 

 type, which is scolopendriform. This fact, which none 

 of the modern lepidopterous writers appear to have 

 perceived, has been so fully illustrated in a series of 

 plates*, as to be placed beyond all reasonable doubt. No 

 better argument, indeed, than this, can be urged against 

 the prevalent but erroneous idea, that the natural ar- 

 rangement of the Lepidoptera, or, in fact, of insects 

 generally, entirely depends upon the form of their ca- 

 terpillars. Our belief is, therefore, that, without a 

 knowledge of the perfect insect, we should never be able 

 to explain whether it was allied to any one particular 

 type by aflSnity, or whether it only analogically repre- 

 sented it. 



iQ5.') Most of the modifications under which the 

 primary types of larvae are in a manner disguised, will 

 be easily comprehended by the foregoing remarks. Iuli- 

 form larvae, as we have already said, are smooth ; but 

 sometimes they are covered with fleshy tubercles, as in 

 the instance of that beautiful butterfly, Polydorus Thoas. 

 Now, the whole structure of the perfect insect shows that 

 it belongs to the iuliform butterfly ; and the reason of 

 its larva being disguised in the form of another type 

 (for the spine- like tubercles on its body are merely soft 

 * Zool. 111. 2dseriesi 



