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186
Remarks. The present genus, established by Mr. Schnitzler, is nearly
allied to PorccUio, though in some points, especially in the very convex body and
its capability of being rolled up into a nearly perfect ball, it exhibits, as it were,
a transition to the next family, the ArmadiUnli'nlir. Mr. B.-Lund describes 7
species of this genus. Of these only a single species is represented in the northern
part of Europe.
Cylisticus convexus (De Geer).
(PI. LXXXI.)
(hiiscits cnure.rus, De Geer, Mem. ties Insectes., Vol. VII. p. 553, PL 35, fig-. 11.
Syn: Porcellio spinifrons, Brandt.
fcem, Koch.
armadilloides, Lex-eboullet.
Specific Charach'rs. Body oblong oval, more than twice as long as it
is broad, side-contours nearly parallel, dorsal face strongly vaulted and perfectly
smooth. Oephalon short, transverse, almost 3 times as broad as it is long, lateral
lobes rather large, obliquely truncated at the tip. median lobe forming a very
small, but distinct acute projection. Side-plates of 1st segment
very large, partly flanking the cephalon. and acutely produced behind;
of mesosome
the succeed-
ing pairs with the posterior corner less acute. Metasome not attaining half
the length of the mesosome, epimeral plates of the first 2 segments concealed,
those of the 3 succeeding segments large, recurved, their lateral margins
being continuous with the sides of the mesosome; last segment about as long as
it is broad at the base, its terminal part conically pointed, and extending
as far
as the basal part of the uropoda. Eyes rather large and convex. Antennulse
with the last joint about as long as the basal one. and conically pointed. Antennae
very slender, considerably exceeding half the length of the body, flagellum
a little
shorter than the last peduncular joint, and having its 2 articulations subequal
in length. Legs moderately slender, and of same structure in the 2 sexes. Inner
mini of 1st pair of pleopoda in male with the terminal parts divergent. Uropoda
rather large, with the basal part oblong quadrangular, and distinctly keeled along
the lower side, outer ramus narrow lanceolate, in male considerably exceeding
the basal part in length; inner ramus very narrow, linear, and issuing far in
front, thus but slightly projecting beyond the basal part. Colour of dorsal face
dark iron grey, with a regular row of light patches along each side of the meso-
some, and in each segment a group of less conspicuous flexuous stripes on either
side of the median line; uropoda generally ferruginous. Length attaining 12mm.