INSTINCT OF INSECTS. 561 



advantages which no other situation could offer. Neither instinct, nor any 

 conceivable modification of instinct, could have taught the ants to avail 

 themselves of a good fortune which but for the invention of glass hives 

 would never have offered itself to a generation of these insects since the 

 creation ; for there is nothing analogous in nature to the constant and 

 equable warmth of such a situation, the heat of any accidental mass of fer- 

 menting materials soon ceasing, and no heat being given out from a society 

 of bees when lodged in a hollow tree, their natural residence. The con- 

 clusion, then, seems irresistible, that reason must have been their guide, 

 inducing a departure from their natural instinct as extraordinary as would 

 be that of a hen which should lay her eggs in a hot-bed, and cease to sit 

 upon them. 



The adaptation of means to an end not likely to have been provided for 

 by instinct is equally obvious in the ingenious mode by which a nest of 

 humble-bees propped up their tottering comb, the particulars of which 

 having before mentioned to you, I need not here repeat. 



There is perhaps no surer criterion of reason than, after having tried one 

 mode of accomplishing a purpose, adopting another more likely to succeed. 

 Insects are able to stand this test. A bee which Huber watched, while 

 soldering the angles of a cell with propolis, detached a thread of this ma- 

 terial with which she entered the cell. Instinct would have taught her to 

 separate it of the exact length required ; but after applying it to the angle 

 of the cell, she found it too long, and cut off a portion so as to fit it to her 

 purpose. 1 



This is a very simple instance ; but one such fact is as decisive in proof 

 of reason as a thousand more complex, and of such there is no lack. 

 Dr. Darwin (whose authority in the present case depending not on hearsay, 

 but his own observation, may be here taken) informs us, that walking one 

 day in his garden, he perceived a wasp upon the gravel walk with a large 

 fly nearly as big as itself which it had caught. Kneeling down he distinctly 

 saw it cut off the head and abdomen, and then, taking up with its feet the 

 trunk or middle portion of the body to which the wings remained attached, 

 fly away. But a breeze of wind acting upon the wings of the fly turned 

 round the wasp with its burthen, and impeded its progress. Upon this it 

 alighted again on the gravel walk, deliberately sawed off first one wing 

 and then the other ; and having thus removed the cause of its embarrass- 

 ment, flew off with its booty. 2 Could any process of ratiocination be more 

 perfect? " Something acts upon the wings of this fly and impedes my 

 flight. If I wish to reach my nest quickly, I must get rid of them to 

 effect which, the shortest way will be to alight again and cut them off." 

 These reflections, or others of similar import, must be supposed to have 

 passed through the mind of the wasp, or its actions are altogether inex- 

 plicable. Instinct might have taught it to cut off the wings of all flies, 

 previously to flying away with them. But here it first attempted to fly 

 with the wings on, was impeded by a certain cause, discovered what 

 this cause was, and alighted to remove it. The chain of evidence seems 

 perfect in proof that nothing but reason could have been its prompter. 3 



An analogous though less striking fact is mentioned by Reaumur, on the 



1 Huber, ii. 268. * Zoonomia, i. 183. 



5 Mr. Newport has argued, in a paper read to the Entomological Society 

 (Trans, i. 228.), that the instinct of wasps is always to cut off the wings of flies 



o O 



