PERFECT SOCIETIES OF INSECTS. 



powerful jaws from posts, rails, and the like. This is carried 

 in its mouth, and is thus ready for immediate use : — but 

 upon this subject I have enlarged in a former letter. The 

 workers also clean the cells and prepare them to receive 

 another egg, after the imago is disclosed and has left it. 



There is good reason for thinking, and the opinion has 

 the sanction of Sir Joseph Banks, that wasps have sentinels 

 placed at the entrances of their nests, which if you can once 

 seize and destroy, the remainder will not attack you. This 

 is confirmed by an observation of Mr. Knight's in the Phi- 

 losophical Transactions 1 , that if a nest of wasps be approached 

 without alarming the inhabitants, and all communication be 

 suddenly cut off between those out of the nest and those 

 within it, no provocation will induce the former to defend it 

 and themselves. But if one escapes from within, it comes 

 with a very different temper, and appears commissioned to 

 avenge public wrongs, and prepared to sacrifice its life in 

 the execution of its orders. He discovered this when quite 

 a boy. 



It sometimes happens that when a large number of female 

 wasps have been observed in the spring, and an abundance of 

 workers has in consequence been expected to make their 

 attack upon us in the summer and autumn, but few have 

 appeared. Mr. Knight observed this in 1806, and supposes 

 it to be caused by a failure of males. 2 I have since more 

 than once made the same observation, and Major Moor, as 

 well as myself, noticed it in the year 1815. "What took place 

 here in the following year may in some degree account for it. 

 Though the summer had been very wet, and one may almost 

 say winterly, there were in the neighbourhood in which I 

 reside abundance of wasps at the usual time ; but except on 

 some few warm days, in which they were very active, 

 benumbed by the cold they were crawling about on the floors 

 of my house, and seemed unable to fly. In this vicinity 

 numbers make their nests in the banks of the river. In the 

 beginning of the month of October there was a very con- 

 siderable inundation, after which not a single wasp was to be 



1 For 1 807, 242—. 



2 Ibid. 243. 



