s divided by a large number of
partitions into vaulted compartments. In the larger ones pillars of
earth support the ceiling. The rooms communicate with one another by
means of bull's-eye passages formed in the separating walls. The whole
is small, proportioned to the size of the works, but excellently
arranged.

When, in the council of the republic, it has been resolved to raise a
common habitation, the workers operate in a singular manner. All the
ants scatter themselves abroad, and with extreme activity take
fragments of earth between their mandibles and place them on the
summit of the dwelling. After some time the result of this
microscopical work appears. The ancient roof, strengthened by all this
material, becomes a thick terrace which the insects first cover very
evenly. The earth, having been brought in grain by grain, is soft and
easy to dig. The construction of the new storey begins at first by the
hollowing out of a number of trenches. The ants scrape away in places
the terrace which they have just made. They thus diminish the
thickness of the layer at the spots where rooms, corridors, etc., are
to be formed, and with the material thus obtained they form walls,
partitions, and pillars. Soon the entire plan of the new storey may be
perceived. It differs essentially from that which Man would adopt; in
the latter case the walls would be shown by the hollowing out of the
foundations; the work of these Hymenoptera, on the contrary, shows
them in relief. These first arrangements made, the six-footed
architects have only to complete their constructions by new deposits
from without. Gradually the storey reaches a sufficient height. It
remains to cover it, and this is not the easiest part of the business.
The ceiling is formed of vaults going from one wall to another, or
from a wall to a column. When one of these vaults is to be small, some
millimetres at the most, the _Formica fusca_ constructs it with the
help of two ledges, which are made facing each other on the tops of
two partitions. These prominences, formed of materials glued together
by saliva, are enlarged by additions to their free edges. They advance
to meet each other and soon join; it is wonderful to see each insect,
following its individual initiative, profit by every twig or fragment
capable of bearing any weight, in order to enlarge the overhanging
ledges.

_Individual skill and reflection._--This personality in work, which
reveals the intelligent