CIIELOSTOMA. 
28 7 
do nothing further to it but collect a sufficient store of 
provender for the nutriment of the young one, upon 
which they deposit the egg which is to produce it. The 
insect then flies away to collect a small quantity of clay 
intermingled with sand, and this they knead together 
by means of a viscous secretion which they disgorge, 
and this forms a concrete that hardens firmly and 
rapidly; to anticipate its rapid drying they speedily fly 
back, carrying this small ball within their mandibles, 
and with it they cover over the provision they have col¬ 
lected, and which, adhering to the sides of the cavity, 
forms a firm and hard division, effectually separating it 
from the next store of provision that is to be accumulated 
for the supply of the larva that will be hatched from the 
egg that is to be deposited, and the same process is 
repeated again and again until all the eggs are laid. In 
their development, which takes place near midsummer, 
the males precede the females by about ten days. They 
associate sometimes in colonies, often using the tubes of 
the straw thatch which covers cottages for their nidus. 
These bees are subject to the parasitical intrusion of 
Fcenus jaculator and assectator, which I have repeatedly 
caught at Battersea, hovering opposite the cells of these 
insects bored in the shingles forming the enclosure of 
an old garden outhouse. These parasites are themselves 
peculiar creatures, forming a type distinct from the 
Ichneumons, and belonging to the group Aulacus, upon 
which see my paper in the ‘ Entomologist/ June, 1841. 
In these insects, the abdomen springs from immediately 
beneath the scutellum. Chrysis cyanea and ignita are also 
bred at the expense of these bees, neither of the species of 
which are uncommon ; the smaller one, the C. campanu- 
larum , which is the smallest of our true bees, excepting 
