38 PREDACIOUS AND PARASITIC 



character which they possess in common with the perfect insect is 

 the rapacious appetite which impels them to attack the other 

 inhabitants of their haunts. The imago, on the other hand, is 

 one of the most beautiful of insects, fulfilling an aerial existence 

 and provided in the most perfect manner with tracheal respiration 

 and ample wings. " The larvae do not live under the same condi- 

 tions as the perfect insects. External forces accordingly affect 

 them in a different manner, and we have seen that they pass 

 through some changes which bear no reference to the form of the 

 perfect insect. These changes are, however, for the most part 

 very gradual." 



These broad characters seem to militate strongly against asso- 

 ciating the Odonata with the Orthopiera ; but when we consider 

 also that, although differing in environment and in certain charac- 

 ters of an adaptive nature, incidental to their surroundings, the 

 larvae of the Odonata strongly resemble those of the Planipennia 

 in general form, in the provision of special mouth structure for an 

 actively carnivorous existence, and in the unwearied hunt after 

 prey, it is hardly possible to escape the conclusion that a near 

 relationship exists between these two groups, and that on these 

 grounds the Linnean arrangement of the Neuroptera should hold 

 good. 



In the Trichoptera (which is an essentially Neuropterous 

 group) and in the Raphidiidce we find that the pupae, though in a 

 great degree quiescent, are, during their later stages, sufficiently 

 active to walk about, thus presenting an intermediate link between 

 the silk-wrapped chrysalis of Hemerobiiis and the active ' pupa ' of 

 Libdhda. The Trichoptera also present, in their habit of catching 

 their prey, many points of resemblance to the Ant-Lions, which 

 will not be without interest to an observant student ; and in wing 

 structure they seem in some respects to favour the venation of 

 Agrion and in others that of Hemerobius. 



To summarise, I am clearly of opinion that, given the principle 

 of evolution (and we are told by Carl Vogt, " personne, en Europe 

 au moins, n'ose plus soutenir la Creation independante et de toutes 

 pieces des especes "), the nature of the metamorphosis in the 

 Neuroptera is only a question of development, and that any par- 

 ticular modification may well arise in any group when the condi- 



