186 _PERFECT SOCIETIES OF INSECTS. 
mediate pair pushes off the pellets. When this is done, 
she, or another bee if she is too much fatigued with her 
day’s labour, enters the cell with her head first, and re- 
mains there some time: she is engaged in diluting the 
pellets, kneading them, and packing them close; and so 
they proceed till the cell is filled*. A large portion of 
the cells of some combs are filled with this bread, which 
one while is found in insulated cells, at another in cells 
amongst those that are filled with honey or brood.— 
Thus it is everywhere at hand for use. 
You have seen how the bees collect and employ two 
of the materials that I mentioned ; I must now advert to 
the third—the Propolis. Huber was a long time un- 
certain from whence the bees procured this gummy re- 
sin; but it at last occurred to him to plant some cuttings 
of a species of poplar (before their leaves were deve- 
loped, when their leaf-buds were swelling, and besmear- 
ed and filled with a viscid juice,) in some pots, which he 
placed in the way of the bees that went from his hives. 
Almost immediately a bee alighted upon a twig, and 
soon with its mandibles opened a bud, and drew from it 
a thread of the viscid matter which it contained; with 
one of its second pair of legs it took it from the mouth, 
and placed it in the basket: thus it proceeded till it had 
given them both their load®. I have myself seen bees 
very busy collecting it from the Tacamahaca (Populus 
balsamifera, L.). But this is an old discovery, confirm- 
ed by recent observation; for Mouffet tells us from Cor- 
dus, that it is collected from the gems of trees, instan- 
cing the poplar and the birch*. Riem observes that it is 
* Compare Reaum. 420, and Huber, ii. 24, with Wildman, 40. 
> Huber, ti. 260. © Insect. Theatr. 36. Schirach, 241. 
