n which to
lay their eggs; some Fish are equally artistic in this kind of
industry, and even certain Reptiles. The Alligator of the Mississippi
would not perhaps at first be regarded as a model of maternal
foresight. Yet the female constructs a genuine nest. She seeks a very
inaccessible spot in the midst of brushwood and thickets of reeds.
With her jaw she carries thither boughs which she arranges on the soil
and covers with leaves. She lays her eggs and conceals them with care
beneath vegetable remains. Not yet considering her work completed, she
stays in the neighbourhood watching with jealous eye the thicket which
shelters the dear deposit, and never ceases to mount guard
threateningly until the day when her young ones can follow her into
the stream.

A hymenopterous relative of the Bees, the _Megachile_, cuts out in
rose-leaves fragments of appropriate form which it bears away to a
small hole in a tree, an abandoned mouse nest or some similar cavity.
There it rolls them, works them up, and arranges them with much art,
so as to manufacture what resemble thimbles, which it fills with honey
and in which it lays.[89] (Fig. 24.)

[89] Reaumur, _Memoires pour servir a l'histoire des
Insectes_, pp. 97 _et seq._

The _Anthocopa_ acts in a similar manner, carpeting the holes of which
it takes possession with the delicate petals of the corn poppy.

The retreats of nocturnal birds of prey do not differ in method of
construction from these two kinds of nests. They are holes in trees,
in ruins, in old walls, and are lined with soft and warm material.
These dwellings are related, not to the type of the hollowed cave, but
to that of the habitation manufactured from mingled materials. They
constitute an inferior form in which the pieces are not firmly bound
together but need support throughout. The cavity is the support which
sustains the real house.

_Dwellings formed of coarsely-entangled materials._--Diurnal birds of
prey are the first animals who practise skilfully the twining of
materials. Their nests, which have received the name of eyries, are
not yet masterpieces of architecture, and reveal the beginning of the
industry which is pushed so far by other birds. Usually situated in
wild and inaccessible spots, the young are there in safety when their
parents are away on distant expeditions. The abrupt summits of cliffs
and the tops of the highest forest trees are the favourite spots
chosen by the great birds