25 
able number of wasps pass the night upon the out- 
side of the tree nest, in warm weather, but the sen- 
tinel is always to be seen at the entrance notwith- 
standing. It may be as well to mention, that in the 
ground nests there are two apertures, one for en- 
trance, and the other for exit. The tree nest has 
usually only one, near the bottom; but in large colo- 
nies a second is often added; in which case there is 
a sentinel stationed at each. 
There is a curious fact with regard to wasps, 
which, though already published, it may be worth 
while to mention, as I have had many opportunities 
of verifying it from experience; viz. that if the en- 
trance to the nest be stopped up in the day time, 
the hundreds of wasps which are constantly return- 
ing to it make no attempt to sting the aggressor ; 
but if one escape from the inside, it attacks him in- 
stantly, though not with the pertinacity of the com- 
mon bee. I have often suffocated the wasps in a 
nest with a mixture of gunpowder and sulphur, in 
the day time, and proceeded to dig them out di- 
rectly, whilst hundreds were flying about me in all 
directions, but I have hitherto escaped with impu- 
nity. If a common quart bottle half full of water, 
is placed in the cavity, and the ground levelled up 
again, so that the mouth of the bottle may as nearly 
as possible occupy the place of the former entrance, 
all the wasps that were absent at the time of the 
taking of the nest, will crowd into the bottle during 
the day; and I have usually found from 500 to 1500 
wasps captured in it on the following morning. It 
is interesting to observe the young wasps eat their 
way through the covering of the cells when their 
transformation is complete. This they will continue 
Cc 
