24 
Kirby and Spencet say, that when the winter sets 
in, “the nest merely serves for the abode of a few 
* benumbed females, and is entirely abandoned at the 
“approach of spring.” I have had frequent oppor- 
tunities of opening nests during the winter, but 
have invariably found them empty, and have reason 
to believe that no females use them as a hyberna- 
culum, but rather prefer seeking a retreat for them- 
selves in the situations already mentioned. 
Some writers have doubted the assertion that a 
sentinel is placed at the entrance of the nest, as soon 
as the wasps retire to rest in the evening; but I can 
state most positively that I have never seen a nest of 
either species, after about nine o’clock in the summer 
months, without observing the sentry at his post; 
and it is curious to see with what rapidity the alarm 
is conveyed to those within, when any attempt is 
made to meddle with him. I have sometimes thought 
that I could see a second sentinel at some distance 
behind the outer one; and judging from the usual 
distance from the entrance down to the nest, (often 
from two to three feet,) and the quickness of the 
communication with it, there may even be more. 
A lantern held near the sentinel does not seem to 
give him any alarm; but on touching the ground 
near him, he instantly disappears for a few seconds, 
and the inhabitants sally out immediately. I always 
capture the sentinel before proceeding to take the 
nest, and they are invariably neuters. A consider- 
males in the preceding autumn. The explanation I have of- 
fered seems a more natural one.—Vide Philosoph. Trans. for 
1807, p. 243. 
' Vol. i. p. 509. 
