591.34 395 



IV. 



The Meaning of Metamorphosis. 



AN article in Nature for December 19, 1895, on "The Transforma- 

 tions of Insects," by Professor L. C. Miall, is so obviously the 

 result of a prolonged consideration of this subject by a gentleman 

 who is well-known for his labours in the field of entomology, and is so 

 important, that it does not seem to us advisable to allow the views 

 brought forward to pass without some marks of dissent from those 

 that hold opinions either partly or wholly distinct from his. 



It is certainly very much to Professor Miall's credit, and of 

 essential service to the advancement of science, that he has taken up 

 this department of research, which, as he correctly states, has been 

 much neglected by entomologists. It is, nevertheless, to be regretted 

 that he has confined his reading before publication to the few works 

 that he mentions, and has consequently not given a complete view of 

 this field of research from a historic standpoint. 



Professor Miall would doubtless have given more consideration 

 to the opinions of other investigators than those who received their 

 inspiration from Darwin's " Origin of Species," and his own 

 researches would have been made more complete, so far as their 

 explanatory hypotheses were concerned, if the possibilities of theories 

 having another origin had been admitted and discussed. 



This author's assertion " that the metamorphoses of insects are 

 fundamentally unlike the transformations of polyps, echinoderms, 

 molluscs, and crustaceans " is founded upon the idea that insect 

 larvae of the so-called higher orders often have resemblances to the 

 adults of more generalised types, such as Thysanura, and on the fact 

 that they pass through their transformations more slowly, these 

 lasting to the sudden and late production of the winged imago 

 or adult. 



There are among insects, as in other branches of the animal 

 kingdom, notable differences in the metamorphoses passed through by 

 individuals belonging to different grades of forms. That these are 

 more remarkable among the more specialised insects, and much more 

 noticeable there than among the primitive forms, goes without saying. 

 This matter has been treated of in the little book " Insecta," written 

 by the authors of this paper, and there the distinction between direct 

 (incomplete metamorphosis) development of the first nine orders of 



