514 INSTINCT OF INSECTS. 



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 a , 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, detach- 

 ed a thread of this material 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, arid cut off a por- 

 tion so as to fit it to her purpose 5 . 



This is a very simple instance ; but one such fact is 

 as decisive in proof of reason as a thousand more com- 

 plex, 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 di- 

 stinctly 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 im- 

 peded its progress. Upon this it alighted again on the 

 VOL. I. 380. b Huber, ii. 268, 



