26 THE ESSEX FIELD CLUB.
Metoecus—a Parasite of Wasps.—Mr. C. Nicholson, F.E.S., exhibited
four female specimens and one male of Metaecus paradoxus, a beetle
parasitic in wasps' nests, and gave a brief account of its life history,
which is as follows:—The eggs are laid in autumn in the crevices
of old wood posts, palings, or tree stumps, and the little black
mite-like larvae, when hatched, remain on the wood until wasps
come to collect the latter as building material for their nest.
The little larva attaches itself to the wasp and is carried in due course
into the latter's nest, where it immediately seeks out a wasp grub into
which it burrows its way and lives on its vital juices until the grub is ready
to spin its cocoon and cover up the mouth of the cell. When this has
been done, the beetle larva comes out of the wasp grub and fastens itself
round the neck of the latter, which it proceeds to finish up, leaving the
empty skin only. The beetle larva then becomes a pupa and, in due
time, a beetle, which sooner or later leaves the nest to fulfil its function
in continuing its kind. The beetles have been found on flowers and can
fly well. The exact time of hatching of the larva is not yet known,
but Dr. T. A. Chapman, who elucidated the life history of this species,
believes that the larvae form in the egg in the autumn, and pass the winter
in the egg shell, hatching in the spring when the worker wasps begin to
appear. The beetle has been taken in Essex. Mr. Nicholson also showed
nests of the following species of wasp. One of Vespa germanica dug up
by himself near Chingford Hatch; one of V. vulgaris consisting of two
"combs" brought with some of the wasps from near Stroud, Glos. The
wasps covered the combs in after the latter had been installed in a box
and placed in the garden. Mr. Nicholson had also taken this nest himself
and had obtained from it the specimens of Metoecus paradoxus exhibited.
He also showed embryo nests of V. norvegica from Rochester and Switzer-
land, and the combs of a larger one built in a gooseberry bush (a
favourite situation with this species) near Stroud; the nest had been
destroyed with tar and solignum, and he had therefore removed the
envelopes. He drew attention to the differences in the architecture and
materials used for the nests, vulgaris using decaying wood, and producing
a brown paper arranged in a shell-like pattern, whilst germanica and
norvegica use fresh wood and produce grey paper, arranged, the former in
somewhat shell-like patches and the latter in continuous sheets.
Mr. Arthur Wrigley exhibited an Earthenware Pot recently found in
alluvial soil at Temple Mills, near Leyton. Although at first sight this
might be taken for an object of some considerable antiquity, it proves
to be. a North-African water-jar of no great age, probably not more than
a century old. Similar vessels have been found in Essex before this;
there are two in the museum at Chelmsford. A photograph of this pot,
kindly taken by Mr. F. Reader, has been deposited in the Essex Museum
of Natural History.
The following papers were read:—"Notes on Leaf-Folding Cater-
pillars," by Ernest Linder, B.Sc., and Charles Key, which in the absence
of the authors was read by Mr. Cole; "Further Records of Epping
Forest Entomostraca" by D. J. Scourfield, F.R.M.S., supplemental to
the papers already published in the Essex Naturalist; "Chalky
Boulder-Clay from Chingford by Percy Thompson.