HABITS AND LIFE-HISTORIES OF WOODLICE. 107
along the back and sides. The head bears side lobes and the
flagellum is three-jointed.
Philoscia muscorum (Scop.), another very active species,
owing to its long legs. About nine millimetres long, light brown
or even yellowish in colour, with darker markings, and with a
smooth, polished surface. The head bears no lobes and the
flagellum is three-jointed. The abdomen is unusually narrow.
Armadillidium vulgare (Latr.), the common "pill-woodlouse,"
distinguished from the rest by possessing the power of rolling
itself up into a ball, like the pill-millipedes. A large species, about
fifteen millimetres long, and the body, which is of a smooth,
shiny and variable shade of brown or grey, is strongly arched.
The head bears a small frontal lobe, and the flagellum is two-
jointed. Like Porcellio spp., the first two abdominal appendages
bear air-tubes of a conspicuous white colour on the ventral side.
II. COLLECTING.
These I collected mainly from Wanstead Park and from
various parts of Epping Forest, but the chalk-loving species
A. vulgare was only found in abundance on the more open chalky
slopes to the north of the county, in the neighbourhood of
Saffron Walden, whilst large numbers of P. dilatatus were supplied
to me by the kindness of Mr. A. Speyer, from the vicinity of
horticultural glasshouses in the Lea valley. Collections and
observations were made on their habits at regular monthly
intervals throughout the year for a period of two and a half
years.
Whenever possible it was found advisable to visit their
haunts after a spell of rain, since the damp draws these moisture-
loving creatures out from their crevices and holes, and conse-
quently they always appear more plentiful at such times. In
fact during the periods of drought in the summer they are
exceedingly difficult to find, and on several occasions I have at
such times been led to assume a species to be entirely absent
from some particular situation, when, even after thorough search-
ing, I have failed to find a single specimen, only to discover on
revisiting the same place after heavy rain that the species is
actually abundantly present. This was particularly the case
with the species T. pusillus and P. muscorum, which during dry