( cxix ) 



instincts were gradually perfected, and that intelligence never 

 came into the history at all. 



It is not from the insects which have had the most varied 

 experience of enemies, most opportunity of learning by contact 

 with danger how to avoid them, and thvxs of developing their 

 nervous systems through use, it is not from these that existing 

 forms have been descended, but from precisely those which 

 have had the least experience. Even for ourselves experience 

 -s spoken of as " the stern guide." To an insect she is apt to 

 )e so stern as to lose all her educational value. The less an 

 iasect sees of her the better the chance of existence and of 

 representation in the generations of the future. The prime 

 recessity for an insect, as for all animals which cannot in any 

 real sense contend with their foes, is to avoid experience of 

 tlem altogether.* 



This is an argument with the broadest possible application 

 t( all Orders of insects. To the adaptive movements of a 

 betle which when disturbed falls to the ground, draws in its 

 liabs and antennae, and looks exactly like a little lump of 

 ea-th ; to the alertness of a fly to take wing before an enemy 

 is within striking distance ; to the perfection of all such 

 mans of defence in insects, and they are numberless, we may 

 aply the words of Browning : — 



" Oh, the little more, and how much it is ! 

 And the little less, and what worlds away ! " 



It is all the difference in fact between success and failure, 

 beween life and death. Comparatively rarely are the con- 

 diions of the struggle such as to admit of partial failure or 

 of mprovement by experience. 



)ne special reason for the passive means of defence adopted 

 bythe vast majority of insects is to be found in the peculiar 

 daigers of their structure. Especially is this true of larvae, 

 wth their hsemolymph contained in freely communicating 



* This argument was brought forward by the present writer in the 

 iiscussion on "Are Acquired Characters Hereditary ? " at the meeting of 

 Section D of the British Association, at Manchester, Sept. 5, 1887 

 [Report, p. 755). No part of the discussion is published. The. argument 

 is however briefly stated in Proc. Boston Society of Nat. History, vol. 

 sxvi, 1894, p. 391, and also quoted in "The Zoologist," Dec. 1900, pp. 

 551, 552. 



