408 VARIATION OF INSTINCT. 



tion of the sweets they furnish, bears equally the character of 

 instinctive prescience. 



Instinct can also on occasion vary as well as err ; often dis- 

 playing, among insects, its capability of accommodating itself, 

 like reason, to circumstances. This is continually exemplified 

 in the case of caterpillars, which, when confined to a box, will 

 employ bits of paper and other chance materials in lieu of the 

 grains of wood or earth with which nature is accustomed to 

 supply them. Another instinctive operation varied to meet 

 exigence is instanced by Reaumur, in the proceedings of a little 

 elm tent-maker, whose tent or case of leaf-skin having been cut 

 open at the side, was sewn up by its little occupant, instead of 

 being supplied by a new one, as unvarying instinct would 

 have prompted. 



We have given, elsewhere, 1 Dr. Darwin's often-quoted 

 anecdote of the wasp and the dead fly, whose wings, when 

 found on trial to be obstructive of its convenient transport, the 

 wasp alighted to cut off. Kirby remarks on this relation, 

 " Could any process of ratiocination be more perfect ? Instinct 

 might have taught it" (as we believe it usually does) " to cut 

 off all the wings of all flies previously to flying ; but here it 

 attempted to fly with the wings on, and was impeded by a cer- 

 tain cause, diccovered what that cause was, and alighted to 

 remove it." Did not the discovery of this cause imply also 

 memory, and a gain of knowledge from experience, by which 

 alone the wasp could have been taught, or reminded, that the 

 wings of the fly were the impediments to his flight have given 

 him at least reason to suspect it from the greater facility with 

 which he had transported bodies that were wingless ? 



A trick, asserted by Huber to be on occasion resorted to by 

 humble-bees for the purpose of extracting honey from flowers 

 that are deeply tubular, has been adduced as another striking 

 instance of the capability of insects to profit by experience. 

 These humming honey-suckers usually extract the nectar from 

 1 " Defence of Wasps." 



