122 Terrestvial Isopoda (Woodlice) of Yorkshire. 
taken it on Fountain’s Fell and Horse Head Moor, and near 
the top of Ingleborough. 
PORCELLIO SCABER var. ALBIDA.—I obtained a pure white 
adult (not newly moulted) under loose limestone rubble at 
Grassington, May, 1914. 
PORCELLIO SCABER var. RUFA Bagnall.—Grassington and 
Keighley, May 1907. 
PORCELLIO PIcTUS Brandt and Ratzburg.—This species 
seems to be able to exist with the least moisture of any of the 
Terrestrial Isopods. It is common on the tops of the dry 
limestone walls of the Craven Highlands. It is a very finely 
marked creature and has one, sometimes three dark bands down 
the back, which is also more or less mottled with bright yellow. 
The head is black, hence one of its synonyms, melanocephalus 
(Schnitzler). It isarather lively creature and when the stones 
on the wall tops are moved, one has to be quick to catch it. 
Malham, T. Stringer, June, 1909; Common on wall tops, 
Gargrave, June, 1909 ; Sedbergh, F. Booth, June, 1909 ; Dibb 
Scar, Grassington, August, 1910; Ingleton, July, 1909; 
Addingham, R. Standon, August, 1911; Forge Valley, Scar- 
borough, September, 1913. 
PORCELLIO DILATATUS Brandt.—I have found this species 
in very many greenhouses around Bradford, but very seldom 
in the open country. 
Sedbergh, F. Booth, June, 1909; Malham, in rubbish from 
old gardens, September, 1913; Manningham, H. Maltby, 
April, 1913 ; Bowling, November, 1913 ; Buckden, June, 1914. 
P. laevis and P. rathkei.—These two species have both been 
taken in Northumberland, so that there is no reason why they 
should not turn up in Yorkshire. 
Genus METOPONORTHUS Budde-Lund. 
METOPONORTHUS PRUINOSUS Brandt.—This is a common 
creature in many greenhouses in the Bradford district, but it 
does not appear to be found often in the open, and then it is in 
the vicinity of gardens. I have taken it in an old chalk quarry 
near Worthing golf links, Sussex, in company with P. laevis, 
both being common, and again in the open at Silverdale, 
Lancashire. 
Lister Park, greenhouses, and on rubbish tip from gardens, 
frequently since 1908; Bowling, 1912 ; Rock-garden, Hare- 
wood Hall, May, IgIt. 
Genus Cy.Listicus Schnitzler. 
CyListIcus CONVEXUS De Geer.—Cylisticus like the true 
pill-woodlice Armadillidium, is able to roll up into a ball, 
but with the antennae exposed. 
This species is fairly common in the mills and dyeworks, 

Naturalist, 
