8i 



THE BRITISH WOODLICE. 



By WILFRED MARK WEBB, F.L.S., and CHARLES SILLEM. 

 (With Plates I. — XXI'., and numerous other Illustrations.) 



[Continued from page 56.] 



In 1857 Kinahan read a paper before the British Association 

 (32) in which he described fourteen species of woodjice from the 

 British Islands, and eleven years later when Bate and West wood 

 published their book (1), the number had risen to seventeen. 

 One of the species (Oniscus fossor), however, was doubtful, and 

 although Dr. Scharff in 1894 (63) rejected it, his list contained 

 also seventeen species, for in the meantime the Rev. T. R. R. 

 Stebbing had found Ligidium hypuorum in Surrey (70). 



Since then the Rev. Canon Norman, Dr. ScharfT, the Rev. 

 T. R. R. Stebbing, and one of the present writers, have added 

 other species, as will be seen from the following pages, in which 

 all those found, up to the present time in the British Islands 

 are described and figured. 



We shall now consider in detail the British genera and 

 species of woodlice and give their synonymy and distribution. 



Order— ISOPODA. 



Tribe— ONISCOIDA. 



Section— L,1GIJE. 



THE TWO DIVISIONS OF THE TAIL APPENDAGES ALIKE IN SHAPE. 



Family— hlGHDM. 



Flagellum with ten or more joints ; tail appendages 



wholly visible ; head without lateral lobes. 



Genus — LIGIA Fabricius, 1798 (27), p. 301. 

 Abdomen broad; body large; habitat, the sea-shore. 



The genus Ligia agrees with Ligidium alone, in that the 

 flagellum of the larger antennae has more than ten joints. In 

 both genera, there are no lateral lobes to the head, and the tail 

 appendages are wholly visible from the upper surface of the 

 body. The latter in Ligia is, however, very many times bigger 

 than in Ligidium and shows no abrupt decrease in the width of 

 its segments when the abdomen is reached. 



