272 HYMKNOPTERA. 
have their enemies ; field mice often de- 
stroy their nests, and polecats sometimes 
make sad havock among them : hut they 
suffer most from some kinds of cater- 
pillars, which eat up the larvae at all 
ages, and now and then even the old 
bees. 
Lucy. When a nest is of its full size 
are there many bees in it ? 
3Iother, Sixty or seventy is the usua^ 
number; but they have been known to 
amount to two or three hundred. 
There are some species of \vild bees, 
which are termed solitary ; instead of 
their habitations being the joint effort of 
the whole society, each female constructs 
a nest for her progeny^ and then returns 
to it no more. 
Lucy. That is like the sphex, who 
builds its nest with so much labour, and 
then leaves it. 
Mother, Just so. The first I shall 
mention is the mason bee, apis muraria*^ 
* From MuruSf a wall. 
