182 



plates of only the 2 anterior pairs of pleopoda with air-cavities. Uropoda with 

 the outer ramus in male nearly twice as long as in female. Colour of dorsal 

 face leaden grey, the segments of mesosome having on each side of the median 

 line an assemblage of lighter, wavy stripes ; lower face and legs pale yellowish. 

 Length of adult male reaching to 15 mm. 



Remarks. The long list of synonyms given above, which could still be 

 somewhat augmented, proves that this species has been described under many 

 different names, a fact that may be accounted for, partly by a certain amount 

 of variability, partly by its occurrence in widely distant parts of the world. Ac- 

 cording to the great authority of Mr. Budde-Lund, all these supposed species are 

 in reality spurious, being referable to the well-known European form P. levels of 

 Latreille. From the other species of the genus, it may be recognized by its 

 comparatively broad and smooth body, the form of the side-plates of the meso- 

 some, and the greatly produced uropoda, partly also by its colour. 



Occurrence. -Though as yet I have no trustworthy knowledge of the 

 occurence of this species in Norway, I regard it as beyond doubt that, on a 

 closer investigation, it will be found to exist somewhere in this country, since its 

 occurrence otherwise has turned out to be almost ubiquitous. The figures here 

 given are from Danish specimens kindly forwarded to me from the Zoological 

 Museum in Copenhagen. According to Mr. Budde-Lund, it is especially found 

 in cellars beneath bakeries, or in other places where a rather high and uniform 

 temperature prevails, sometimes also in refuse-heaps close to the towns. It is 

 said to be not particularly agile in its movements. 



Distribution. Sweden, Denmark, Germany, Belgium, Britain, France, Austria, 

 Spain, Italy, Dalmatia, Greece, Turkey, Tunis, Syria, Egypt, Turkestan, Madeira, 

 Azores, North America, Mexico, West-Indies, Peru, Brazil, Chili, Pacific Islands. 



6. Porcellio Ratzeburgii, Brandt. 



(PI. LXXX, fig. 1.) 

 Porcellio Ratzeburgii, Brandt, Consi,. monogr. Crust. Isop. terrestr., p. 13, fig. 3. 



Syn : Porcellio nemorensis, Koch. 

 quercuum, Sclmitzl. 



lugubris, Koch. 



^l><'dfic Characters. Body oblong oval, with the sides almost parallel, 

 dorsal face slightly convex, and obtusely granular in the middle of the segments. 

 Cephalon almost wholly flanked by the side-plates of the 1st segment of meso- 

 some, lateral lobes rather large, and narrowly rounded at the tip, frontal lobe 

 very prominent and evenly curved, almost semicircular. Side-plates of mesosome 



