PORCELLIO PICTUS. 481 
form of the body is that of P. scaber, but the compara- 
tively small amount of granulation of the upper surface, 
with the short triangular terminal segment of. the tail 
pointed acutely at its tip, will serve to distinguish it, 
independent of its coloration and marking, 
The head is entirely black and strongly granulated, 
the granules of the hind part of the head being arranged 
in transverse rows; the ground colour of the remainder 
of the animal is that of yellowish clay. The anterior 
half of the first segment of the body has a black streak 
extending down the middle, on each side of which is a 
bright yellow patch, with a black spot on each side 
behind the eyes. These spots reappear in the following 
joints, the central black one being widened, and the yellow 
one on each side nearly forming a ring, enclosing a dark 
spot and some dark dots; the lateral margins are yellow, 
with groups of black dots near the edges, and a sub- 
marginal black streak on each side parallel with the 
margin. The basal portion of the apical appendage 
of the tail is yellow, and the broad outer division black, 
with the tip pale. The outer antennz are dusky, the 
sixth joint being evidently longer than the terminal one. 
The several varieties above quoted, given as distinct 
species by Koch, vary in the greater or less clearness of 
the dark longitudinal stripes down the back ; in P. serialis 
these dark stripes alternate in nearly equal width with 
the intervening pale ground of the body, leaving in fact 
a pale central and two narrow streaks parallel with the 
sides of the body, together with a broader or less clearly 
defined one on each side of the dark lines at the edges of 
the central pale one. 
In its general form and appearance it resembles Oniscus 
fossor, from which it however differs in being far more 
glossy and variegated in colour. 
VOL. Il. et 
