352 ME. a, LEWIS ON JAPAITESE LAKGTTEIIDiE. 



of these families beyond what their mode of life and its environ- 

 ment would lead us to expect. By analogous forms I mean forms 

 agreeing in fades, with an approximate structure of appendages, 

 these correspondences being evidently connected with the habits 

 and surroundings of the species, and primarily caused by the 

 conditions under which they exist. In the Langitria trifoliata, 

 Harold, already referred to, we have an outline which is, for this 

 group, very considerably modified — " elytris post basin subam- 

 pliatis," with the apex opening or dehiscent. This insect is so 

 quick on the wing that it is difficult to capture.. Here is a dif- 

 ference in habit accompanied by a corresponding deviation of 

 form, and evidently in some way correlative. 



It cannot be said that the fashioning of the Languriidse is the 

 result of influences affecting the insect in some early stage (as 

 larva or pupa) before the imago appears, because we see through- 

 out the whole of the insect world that in each stage of an insect 

 forms are assumed which are adapted solely to such stage, and 

 are entirely free and uncontrolled by any external structure of 

 the individual during any antecedent stage of its existence. 

 Each, as a larva or imago, is formed for its environment to crawl 

 or fly, and a process, which is not immediately obvious, checks 

 in all its stages variation or an abrupt departure from the type 

 of its predecessor. 



I say acquiring and retaining their form, because, owing to 

 the continuity of action in all natural forces which produce a 

 permanent effect on the structure and composition of any 

 animal, we cannot separate the creative from the preservative 

 process. 



A reference to a certain phase in the Vegetable Kingdom will 

 illustrate my meaning. I take an Oak as the ordinary type of 

 growth in a plant under normal conditions. In a full-grown tree 

 the greatest circumference is in the part just above the root, the 

 part which is half in, half out of the ground. This part repre- 

 sents the first growth in the acorn, which maintains a proportional 

 bulk throughout the lifetime of the tree. The growth of vege- 

 tation in England is checked in autumn by the falling tempe- 

 rature, and the circulation in the tissue of a tree is stopped 

 in all its parts (in a climate where growth is slow) almost at 

 once. But let me picture an area nearer the tropics, such as 

 many travellers have seen, in which during part of the year copious 

 rain falls, and is then abruptly followed by a lengthened period 



