220 THE ESSEX NATURALIST.
of the pupa and the use of the hooks are confirmed by later
observations of Miger. This naturalist published7 in 1809
a very concise account, with illustrations, of the metamorphoses
of the insect. He states that his larvae went into the earth
(apparently without any difficulty) using their mandibles and
their feet for digging. They buried themselves two inches
deep and took five days to form a cavity by compressing the
earth in all directions with their body The cavity was almost
spherical, and did not appear to have any opening. The further
descriptions agree very closely with those of Lyonnet,
Although I subsequently obtained other larva; from the
Eastbourne marshes, unlike Miger, I was quite unable to get
any of them to bury themselves naturally in the earth. When
speaking about the subject to my Coleopterist friend, Mr. E. C.
Bedwell, I asked him if he had ever found the pups, and he
informed me that he had seen them on turning over a board lying
on the ground near a ditch in a locality frequented by the
beetles. Each was in a cavity which was exposed when the
board was removed, exhibiting the white pupa inside.
This interesting observation gave me the clue to the problem,
and I followed it up at the first opportunity. A box containing
damp earth slightly pressed down was partly covered with a
sheet of glass, which was weighted by a piece of brick. A slight
hollow was made below the middle of the free edge of the glass
and a full-fed larva which had just come out of the water was
put on the exposed portion of the earth. After a short rest the
larva began to investigate its surroundings. It discovered the
hollow and promptly at that place began to burrow its way
under the glass. By removing the brick at intervals it was seen
that the larva was making its way downwards and forming a
spherical cavity by forcing apart the loosely packed earth.
The cavity was shaped and the wall smoothed by pressure
and when completed was apparently cemented by some hardening
material.
When handled a larva will sometimes rapidly contort its
body and eject a black fluid from the anus. The intestine must
be emptied before the changes towards pupation begin and the
fluid waste matter may perhaps be used as plaster.
Several other larvae adopted the same procedure of making
7 Annales du mus. d'histoire, xiv., 445.