96 THE BRITISH WOODLICE.
The fact that Porcellio dilatatus is more than half as broad
as it is long at once distinguishes it from the other species of
Porcellio. It is tuberculated and of somewhat
a lighter grey than Porcellio scaber usually is.
The two species agree in having the two joints
of the flagellum equal, but the last peduncular
joint, as in Porcellio pictus, is longer than the
flagellum.
As in the two preceding species, air-tubes
are found in the outer plates of the appendages
on the first two abdominal segments. Porcellio
dilatatus is to be looked for near houses.
BRITISH LOCALITIES :—
England: Maldon; (W.M.W. from R.M.) :
Eton ; (Stebbing from W.M.W., 71a) : Berk-
hamsted ; (Norman, 50) : Headley, Surrey ;
Ventnor ; (Stebbing in Norman, 49).
Ireland : Dublin ; (Scharff, 63) : Dundrum ;
(Scharff in Norman, 50): Gatway ; Roundstone ;
(R.F.S.): Belfast ; (C. W. Buckle, Irish Nat., Vol. XI. (1902),
p. 43).
FOREIGN DISTRTBUTION :—
Europe : Fiance ; (25) : Spain ; (12) ; Denmark; Norway ; Germany ; Poland ;
Holland; (59).
Africa : Madeira ; Azores; (24).
Australia: New Guinea ; (59).
Porcellio rathkei Brandt. Plate XVI.
1833 Porcellio rathkei Brandt (3), p. 177, fig. 10.
1833 Porcellio ferrugineus Brandt (3), p. 178.
1840 Porcellio trilineatus Koch (34). part 34, pl. IX.
1853 Porcellio trivittatus Lereboullet (39), p. 54, pl. I., figs. 13 and 14.
1853 Porcellio tetramoerus Schnitzler (65), p. 24.
1853 Porcellio striatus Schnitzler (65), p. 24.
There is often a light band down the back and one on either
side of it near the margin in Porcellio rathkei (especially in the
males), with other more irregularly arranged light patches
between. Unlike the three species previously considered, the
present one has a smooth body. The distal joint of the flagellum
is the longer, and the flagellum itself is equal in length to the
last joint of the peduncle.