[Footnote 2: Mr. E. L. Layard has given an interesting account of this
Mason wasp in the _Annals and Magazine of Nat. History_ for May, 1853.

"I have frequently," he says, "selected one of these flies for
observation, and have seen their labours extend over a period of a
fortnight or twenty days; sometimes only half a cell was completed in a
day, at others as much as two. I never saw more than twenty cells in one
nest, seldom indeed that number, and whence the caterpillars were
procured was always to me a mystery. I have seen thirty or forty brought
in of a species which I knew to be very rare in the perfect state, and
which I had sought for in vain, although I knew on what plant they fed.

"Then again how are they disabled by the wasp, and yet not injured so as
to cause their immediate death? Die they all do, at least all that I
have ever tried to rear, after taking them from the nest.

"The perfected fly never effects its egress from the closed aperture,
through which the caterpillars were inserted, and when cells are placed
end to end, as they are in many instances, the outward end of each is
always selected. I cannot detect any difference in the thickness in the
crust of the cell to cause this uniformity of practice. It is often as
much as half an inch through, of great hardness, and as far as I can see
impervious to air and light. How then does the enclosed fly always
select the right end, and with what secretion is it supplied to
decompose this mortar?"]

_Wasps_.--Of the wasps, one formidable species (_Sphex ferruginea_ of
St. Fargeau), which is common to India and most of the eastern islands,
is regarded with the utmost dread by the unclad natives, who fly
precipitately on finding themselves in the vicinity[1] of its nests,
which are of such ample dimensions, that when suspended from a branch,
they often measure upwards of six feet in length.[2]

[Footnote 1: In ought to be remembered in travelling in the forests of
Ceylon that sal volatile applied immediately is a specific for the sting
of a wasp.]

[Footnote 2: At the January (1839) meeting of the Entomological Society,
Mr. Whitehouse exhibited portions of a wasps' nest from Ceylon, between
seven and eight feet long and two feet in diameter, and showed that the
construction of the cells was perfectly analogous to those of the hive
bee, and that when connected each has a tendency to assume a circular
outline. In one specimen where there were three cell