508 INSTINCT OF INSECTS. 
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 say 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 
