52
THE BRITISH WOODLICE.
so in fact, that any of his species that happen to find him will
attack him and eat all his front half, rejecting, however, his now
hardened tail-end.
Provided that the moulting Woodlouse has survived (and in
captivity, to ensure this, he must be isolated), after three days
his jaws will be sufficiently hardened to allow of his eating, and
usually he first of all devours the second half of his cast skin.
The operation of moulting does not occupy quite so long a time
in the case of young examples. Specimens half-an-inch long do
not moult more than once in six months and show but little
increase in size after the process.
Woodlice do not appear to live on either animal or vegetable
food alone, but adopt a mixed diet. It is, however, owing to
their attacks upon cultivated plants that the creatures are
looked upon as pests by the horticulturalist. The animals feed
either in the night or in the very early morning, on seedlings,
orchid tubers, mushrooms, or anything that comes to hand. Few
of the accounts, however, of their ravages, mention that the
crustaceans have been caught absolutely in the act of doing
the damage ascribed to them. Some careful inquiries have
nevertheless enabled us to discover several observers who
have watched woodlice feeding. Mr. F. V. Theobald, of Wye
College, and one of the students at Swanley Horticultural
College are among the number. The former has also given us an
account of the methods, out of many tried, which he has found
most successful for getting rid of the crustaceans. Out of doors
trapping with moss, sacking or horse-dung is best. In glass
houses, fumigation with hydro-cyanic acid gas has cleared them
out, and poison baits, especially potatoes cut and soaked in
white arsenic, have done some good. Stable manure is especially
favourable to these creatures, particularly when it is used "long":
in this condition it should therefore be avoided.
It is interesting to note how the woodlice in winter simply
remain where they happen to be so long as there is sufficient
moisture, though they are ready to run about as rapidly for a
time as in summer, should they happen to be disturbed.
No doubt many points of inter-relation between woodlice
and other animals remain to be discovered. Mr. John W. Odell
tells us that on Exmoor, in the open, he found no Armadillidium
though other forms occurred under nine out of every ten stones