_Ireland_: Dublin; (Scharff, 63): Dundrum; (Scharff in Norman, 50): Galway; Roundstone; (R.F.S.): Belfast; (C. W. Buckle, Irish Nat., Vol. XI. (1902), p. 43). _FOREIGN DISTRIBUTION:--_ _Europe_: France; (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. Some specimens found by Mr. Webb in 1899 at Eton were submitted to Mr. Stebbing, and since then the former has found _Porcellio rathkei_ to be pretty generally distributed in West Middlesex, where the species appears to frequent the open fields. Air-tubes occur in abdominal appendages 1 to 5 and the white appearance of all of these at once serves to distinguish the living animal from _Porcellio scaber_ in which the first two pairs of abdominal appendages alone are white. _BRITISH LOCALITIES:--_ _England_: Eton; (Stebbing, 71a): Lane End; (Stebbing, from the Misses Johnston, 71a): Acton; Ealing; Hanwell; Southall; Northolt; Greenford; West Drayton; Mortlake; (W.M.W.); Sunderland; (Brady, 50a). _FOREIGN DISTRIBUTION:--_ _Europe_: France; (25): Bosnia; Servia; (22): Hertzogovania (B.M.); Norway; Northern, Western, and Middle Europe, everywhere; (59): Corfu (B.M.) _Asia_: Transcaucasia; (59). _North America_: (59). [Illustration: FIG. 50.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE ANTENNA OF _Porcellio rathkei_.] =Porcellio laevis= Latreille. PLATE XVII.