246 HABITATIONS OF INSECTS. 
cieties, built by the united labours of many. The former class may be 
conveniently subdivided into habitations built by the parent insect, not for 
its own use, but for the convenience of its future young ; and those which 
are formed by the insect that inhabits them for its own accommodation, 
To the first I shall now call your attention. 
The solitary insects which censtruct habitations for their future young 
without any view to their own accommodation, chiefly belong to the order 
Hymenoptera, and are principally different species of wild bees and wasps. 
Of these the most simple are built by Colletes* succincta, fodiens, &c. The 
situation which the parent bee chooses, is either the dry earth of a bank, 
or the vacuities of stone walls cemented with earth instead of mortar. 
Having excavated a cylinder about two inches in depth, running usually 
in a horizontal direction, the bee occupies it with three or four cells about 
half an inch long, and one sixth broad, shaped like a thimble, the end of 
one fitting into the mouth of another. The substance of which these cells 
are formed is two or three layers of a silky membrane, composed of a kind 
of glue secreted by the animal, resembling gold-beater’s leaf, but much 
finer, and so thin and transparent that the colour of an included object 
may be seen through them. As soon as one cell is completed, the bee 
deposits an ege within, and nearly fills it with a paste composed of pollen 
and honey ; which having done, she proceeds to form another cell, storing 
it in like manner until the whole is finished, when she carefully stops up 
the mouth of the orifice with earth. Our countryman Grew seems to 
have found a series of these nests in a singular situation—the middle of 
the pith of an old elder branch—in which they were placed lengthwise 
one after another with a thin boundary between each. 
Cells composed of a similar membranaceous substance, but placed in a 
different situation, are constructed by Anthidium manicatum$ This gay 
insect does not excavate holes for their reception, but places them in the 
cavities of old trees, or of any other object that suits its purpose. Sir 
Thomas Cullum discovered the nest of one in the inside of the lock of a 
garden-gate, in which I haye also since twice found them. It should 
seem, however, that such situations would be too cold for the grybs with- 
out a coating of some non-conducting substance. The parent bee, there- 
fore, after having constructed the cells, laid an egg in each, and filled them 
with a store of suitable food, plasters them with a covering of vermiform 
masses, apparently composed of honey and pollen ; and having done this, 
aware, long before Count Rumford’s experiments, what materials conduct 
heat most slowly, she attacks the woolly leaves of Stachys lanata, Agro 
stemma coronaria, and similar plants, and with her mandibles industriously 
scrapes off the wool, which with her fore-legs she rolls into a little ball 
and carries to her nest. This wool she sticks upon the plaster that 
coyers her cells, and thus closely envelops them with a warm coating of 
down, impervious to every change of temperature.* 
1 Melitta. *. 9. K. 
* a Grew’s Rarities of Gresham College, 154. Kirby, Mon. Ap. Angl. i. 181. Me 
uta, *. a. 
5 Curtis, Brit. Ent. t. 61. 
4 Mon. Ap. Angl.i.173. Apis. **. c. 2. c. Prom later observations I am inclined 
to think that these cells may possibly, as in the case of the humble bee, be in fuct 
formed by the larva previously to becoming a pupa, after having eaten the provision 
