120 THE HUMBLE-BEE vil 
difficulty in obtaining access to the holes from the 
inside, and to this defect, which was afterwards put 
right by filling the inside of the lid with clay, I owed 
the loss of three mothers of families. No brood was 
injured or destroyed in the nests protected by these 
mouse excluders, but by the time they were placed 
in position most of the nests had almost passed 
through the period of danger, for I have never seen 
a nest containing workers injured by a mouse. 
No doubt there are other animals that may 
destroy the brood of the humble-bee. Slugs and 
millipedes are vegetable feeders, and I have no 
evidence that they did any direct harm to the brood 
in my nests; indeed, | think they never entered the 
nests as long as the latter remained fairly dry. 
But the common centipede (Lzthobzus) 1 regarded 
with considerable suspicion, for it is carnivorous, 
and also very active. Several times I found these 
centipedes in the cavities containing nests occupied 
by my queens, and once I saw one biting some 
cocoons I had lifted out of a deserted nest and had 
left lying on the ground for half an hour. 
To the above causes of loss I must regretfully 
add another—my own blundering. 
It has been mentioned that the queens are liable 
to forsake their nests if they are disturbed in them, 
and that very little interference causes a queen to 
desert her brood when it is young, but that after 
the cocoons are spun she becomes more attached to 
it, and when the workers are about to emerge only 
a severe fright will cause her to abandon it. A 
