502 INSTINCT OF INSECTS. 



that fly abroad, what conception can we form of the 

 cause which, while one set is gathering honey or pollen, 

 leads another company to load their legs with pellets of 

 propolis ? Are we to sa^ that the instinct of the former 

 is excited by one sensation, that of the latter by another? 

 But why should one sensation predominate in one set of 

 bees, while another takes the lead in a second ? or how 

 is it that these different instincts are called up precisely 

 in the degree which the actual and changing state of 

 things in the hive requires ? Of those which remain at 

 home, what is it that determines in one party the instinct 

 of building cells to prevail ; in another that of ventilating 

 the hive ; in a third that of feeding the young brood ? 

 For my own part, I confess that the more I reflect on, 

 this subject, and contrast the diversity of the means with 

 the regularity and uniformity of the end, the more I am 

 lost in astonishment. The effects of instinct seem even 

 more wonderful than those of reason^ in the same man- 

 ner as the consentaneous movements of a mighty and 

 divided army, which, though under the command of 

 twenty generals and from the most distant quarters, 

 should meet at the assigned spot at the very hour fixed 

 upon, would be more surprising than the steam-moved 

 operations, however complex, of one of Boulton's mints. 

 For the sake of distinctness and compression, I have 

 confined myself in considering the number of the in- 

 stincts of individual insects to a single species, the bee ; 

 but if the history of other societies of these animals 

 wasps, ants, &c. detailed in my former letters, be duly 

 weighed, it will be seen that they furnish examples of 

 the variety in question fully as striking. These corro- 

 borating proofs I shall leave to your own inference, and 



