168 



the last peduncular joint, and composed of 3 articulations, the last terminating 

 in a dense bunch of delicate hair-like bristles. Last pair of legs in male com- 

 paratively more strongly built than in female, but otherwise of a very similar 

 structure. Uropoda with the rami nearly equal and somewhat longer than the 

 basal part. Colour pure white, semipellucid. Length of adult female 3 mm. 



Remarks. — This form was first described by Zaddach in the year 1844 

 as Itea Mengii, being referred to the Kochian genus, which is identical with 

 Trichoniscus of Brandt. In the year 1860 Mr. Schobl examined the same form, 

 and regarded it as new to science, describing it as the type of a new genus 

 under the name of Haplophthalmus elegans. It is easily distinguished from the 

 2nd species by the very distinct and regular longitudinal ribs on the dorsal face 

 of the mesosome, and by the rather conspicuous dorsal prominences of the 3rd 

 segment of the metasome. 



Occurrence. — I first met with this pretty form, hitherto not recorded from 

 any of the Scandinavian countries, early in the spring of this year (1897) on the 

 steep banks of a little river at some distance from Christiania, where it occurred 

 rather plentifully, deeply concealed in the crevices of mouldering argillaceous 

 slate. The females at that time were laden with eggs and young, and male 

 specimens occurred almost as abundantly as females. Subsequently I found it 

 in 2 other places, likewise in the neighbourhood of Christiania, beneath stones 

 and pieces of old wood. It moves very slowly, and, in spite of its small size, 

 is easily detected by the pure white colour of the body. 



Distribution. — Prussia, Germany, Bohemia, France. 



2. Haplophthalmus danicus, Budde-Lund. 



(PI. LXXIV, fig. 2.) 

 Haplophthalmus danicus, Budde-Lund, Prosp. gener. spec, crust. Isop. tevrestr., p. 9. 



Syn: Haplophthalmus elegans, B.-Lund (olim). 

 „ ,. Mengii, Weber (not Zaddach). 



Specific Characters. — Form of body resembling that of the preceding 

 species, being, as a rule, somewhat shorter and compacter in male than in female; 

 dorsal face very rough on account of numerous, somewhat unequal tubercles arranged 

 in longitudinal rows, though not forming distinctly defined ribs, as in H. Mengii. 

 Cephalon with the front acutely produced, lateral lobes broadly rounded. Side- 

 plates of mesosome as in H. Mengii. Metasome nearly smooth above, without 

 the slightest trace of any prominences on the 3rd segment. Appendages of body 

 almost exactly agreeing in structure with those in the preceding species, except 



