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 antennae 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. IT. I J 



