MEANS OF DEFENCE OF INSECTS: 967 
often barricade the entrance of their hive by a thick wall 
made of wax and propolis. This wall is built imme- 
diately behind and sometimes in the gateway, which it 
entirely stops up; but it is itself pierced with an opening 
or two sufficient for the passage of one or two workers. 
These fortifications are occasionally varied: sometimes 
there is only one wall, as just described, the apertures of 
which are in arcades, and placed in the upper part of 
the masonry. At others many little bastions, one be- 
hind the other, are erected. Gateways masked by the 
anterior walls, and not corresponding with those in them, 
are made in the second line of building. These case- 
mated gates are not constructed by the bees without the 
most urgent necessity. When their danger is present 
and pressing, and they are as it were compelled to seek 
some preservative, they have recourse to this mode of 
defence*, which places the instinct of these animals in a 
wonderful light, and shows how well they know how to 
adapt their proceedings to circumstances. Can this be 
merely sensitive ! ? When attacked by strange bees, they 
have recourse to a similar manceuvre; only in this case 
they make but narrow apertures, sufficient for a single 
bee to pass through.——Pliny affirms that a sick bear will 
provoke a hive of bees to attack him in order to let him 
blood®. What will you say, if humble-bees have re- 
course to a similar manceuvre? It is related to me by 
Dr. Leach, from the communications of Mr. Daniel Byd- 
der—an indefatigable and well-informed collector of in- 
sects, and observer of their proceedings—that Apis ter- 
« Huber, Nouv. Obs. ii. 294— b Hist. Nat. \. viii. c. 36. 
