THE BRITISH WOODLICE. 
Genus -LIGIDIUM Brandt, 1833 (3), 
Zia, Koch (34). 
2c 
Pp. 173 
Abdomen narrow ; habitat, wet moss. 
In Ligidium there are numerous joints to the flagellum, lateral 
lobes are absent from the head, and the tail appendages are com- 
pletely to be seen. All the segments of the abdomen are 
distinctly narrower than those of the thorax and in this it agrees 
with Tvichoniscus, Trichoniscotdes, Philoscia, and Metoponorthus. 
In these, however, the flagellum has never more than seven 
joints, the tail appendages (as in all genera 
but Ligia and 
Ligidium) are partially hidden by the last segment, and in all the 
four but Philoscia there are lobes to the head. 
Ligidium hypnorum, Cuvier. P aie II. 
1792 Oniscus hypnorum Cuvier (9), pl] XXVI., figs. 3—5. 
1793 Oniscus agilis Persoon, quoted by Koch in Panzer (51), part 5, pl. XXIV. 
1830 Ligia hypnorum Bosc (2). p. 179. 
1833 Ligidium persoonit J. F. Brandt (3), p. 174, pl. Votes: 6—7. 
1840 Zta agilis Koch (34), part 34, pls. XXII, and XXIII. 
1844 Ligidium persontt Zaddach (77), p. 17. 
1853 Ligidiuim personit Lereboullet (39), p. 14, pl. I., fig. 1, pl. I., figs. 2o—31. 
1857 Ligtdium personit Kinahan (32), p. 275, pl. XXL., fig. 
» 1873 Zita saundersit Stebbing (70), p. 286. 
1873 Ligtdiuim agile Norman (48), p. 419. 
1885 Ligidium hypnorvum Budde-Lund (8), p. 254 
14, pl. XXII., fig. 9. 
1898 Ligidium hypnovum G. O. Sars (59), p. 158 pl. LXXI. 
This species, which like the last, is the only British 
representative of its genus, was added to our 
fauna in 1873 by the Rev. Thomas R. R. 
Stebbing (70) who found specimens in the 
neighbourhood of Copthorne Common, Surrey. 
Up to the present time, when we are pleased 
to announce that we discovered it in the 
spring of 1902 at Warley in Essex, Ligidinm 
hypnovum has not been recorded from any other 
place in the British Islands. 
As the name of the species implies, it lives 
in wet situations and in its turn connects Ligia 
with the forms which inhabit drier places. 
Ligidium hypnorum might be mistaken for 
Philoscia muscorum, but as already pointed out in 
the generic description, the latter has but a few 
(three) joints to the flagellum, instead of from 
ten to thirteen. From Ligia, the species under 
FIG, 36.—FLAGELLUM 
AND LAST PEDUNCULAR 
JOINT OF THE ANTENNA 
oF Ligidium hypnorum 
consideration is distinguished by its small size, narrow abdomen, 
and habitat. 
