138 THE ESSEX NATURALIST.
Cupressus nootkatensis Don ; Yellow Cypress. C.
C. Lawsoniana Murr. ; Lawson Cypress. C. G. F.
C. pisifera Koch ; Sawara Cypress. C. G.
var. plumosa Mast. G.
Thuja orientalis L. ; Chinese Arbor-vitae. C.
var. aurea Hort. C.
Juniperus Sabina L. ; Savin. C.
Taxaceae.
Taxus baccata L. ; Common Yew. P. W. C.
Ginkgoaceae.
Ginkgo biloba Kaempf. ; Maidenhair Tree. W.
THE HABITS AND LIFE-HISTORIES
OF WOODLICE.
By WILLIAM HEELEY, B.Sc., Ph.D.
[Read 25th January, 1941.]
(Conclusion.)
(Continued from page 114.)
THE question of food supply in these creatures appears
to be an ecological factor of only secondary importance,
and woodlice can, in fact, like many Crustacea, live for months
without food, though seldom living more than a week under
unsuitable humidity conditions. Their food consists of almost
any kind of vegetable matter such as fungi, algae, succulent
plants and root vegetables, though some species, especially
O. asellus, are decidedly more omnivorous than others, such as
P. scaber, which confines its diet largely to the bark of trees, and
T. pusillus, which lives almost entirely on decaying leaves in
nature. Where they occur in large numbers they may become
a serious menace to horticulturalists, damaging seedling plants
and garden crops, though on their credit side it may be claimed
that they often act as valuable scavengers. Pierce (1907) and
Collinge (1915) have referred to their economic importance in
some detail.
Their apparent impartiality for any particular kind of food
soon became obvious when keeping them in captivity, and I
found that, with only one exception, all the species took readily