264? MEANS OF DEFENCE OF INSECTS. 



often barricade the entrance of their hive by a thick 

 wall made of wax and propolis. This wall is built im- 

 mediately behind and sometimes in the gateway, which 

 it entirely stops up; but it is itself pierced with an open- 

 ing or two sufficient for. the passage of one or two work- 

 ers. These fortifications are occasionally varied : some- 

 times there is only one wall, as just described, the aper- 

 tures of which are in arcades, and placed in the upper 

 part of the masonry. At others many little bastions, 

 one behind 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 

 casemated gates are not constructed by the bees without 

 the most urgent necessity. When their danger is pre- 

 sent and pressing, and they are as it were compelled to 

 seek some preservative, they have recourse to this mode 

 of defence a , 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 manoeuvre ; 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 5 . What will you say, if humble- 

 bees have recourse to a similar manoeuvre ? It is re- 

 lated to me by Dr. Leach, from the communications of 

 Mr* Daniel Bydder an indefatigable and well-inform- 

 ed collector of insects, and observer of their proceedings 

 that Bombus c terrestris, when labouring under Aca- 



3 Huber, Nouv. Obs. ii. 294 b Hist. Nat. 1. viii. c. 36. 



c Apis. * *. e. 2. K. 



