RHYSODESMUS. 203 
The following species are unknown to me, except from their figures and 
descriptions :— 
15. Rhysodesmus acolhuus. 
Polydesmus (Fontaria) acolhuus, Humb. & Sauss. Rev. et Mag. Zool. (2) xxi. p. 150 (1869); Miss. 
Sci. Mex., Myr. p. 33, t. 2. fig. 2 (1872) ”. 
Colour: the dorsal surface yellowish and traversed by two blackish olive-green lateral bands composed of a 
large patch on each metazonite, and represented on the first tergal plate by two converging patches ; 
a median narrow stripe of the same colour on the middle of the prozonites; sides and lower surface 
blackish-green ; head blackish, with a tricuspidate frontal patch and pale labrum ; antenne testaceous, 
dark apically. 
@. Body moderately vaulted. eels almost following the slope of the back, lightly raised at the extremity ; 
keels of segments 1-4 or 5 with their posterior border directed obliquely forwards; those of the ten 
following segments quite transverse, the posterior border straight and in the same line as that of the 
median area of the segments; posterior border on the following segments directed obliquely backwards ; 
keels from the 2nd to the 15th very round, the posterior angle rounded but squarer than the anterior ; 
from the 16th to the 19th the posterior angles become progressively more angular; marginal thickening 
tolerably wide and thick ; pores superior and median. Caudal process longer than wide. Dorsal surface 
a little striolated, rugulose or subsquamous at the base of the keels ; the keels coriaceous. 
g. Smaller and much flatter than the 9 , with the keels horizontal. 
Length, 2, 50 millim., width 9°5. 
yy 6 6S AE » 8. 
Hab. Mexico, Valley of Moyoapan and the Sierra de Agua, near Orizaba, in the 
Eastern Cordillera + ?. 
16. Rhysodesmus angelus. (Tab. XV. fig. 14.) 
Polydesmus (Fontaria) angelus, Karsch, Arch. f. Naturg. xlvii. p. 39, t. 3. fig. 13 (1881) '. 
Fontaria tepaneca, Attems, Denk. Akad. Wien, lxviii. p. 259, t. 13. fig. 318 (1890)* (? Fontaria 
tepaneca, Sauss.). 
Colour (when not decolorized) castaneous with yellow keels. 
Body vaulted, smooth and shining, rugulose. The ‘eels following the slope of the back, their anterior angles 
rounded, posterior angles of segments 2-4 also rounded, those of 5-13 almost rectangular, and those of 
16-18 forming a wide short tooth ; those of 19 forming a rounded lobe. Sterna smooth, not hairy, with 
cross-shaped sulcus. 
Phallopod cylindrical and straight, distally narrowed (? when seen from below); when seen from the side, the 
principal branch is very stout, longer than the palmar portion of the organ, with both its upper and lower 
edge markedly sinuous ; its apex is distinctly upcurled and somewhat strongly bifid; the interramal space 
is wide and rounded; and the auxiliary branch, which is rather less than half the length of the palmar 
portion, is slender, projects obliquely forwards and upwards, with lightly convex upper border and nearly 
straight lower border, the entire branch being only very slightly curved. 
Length, 2, 50 millim., width 9°5. 
” oi 42 9 ” 8:5. 
Hab. Mexico, Puebla!? (Hamburg Museum). 
So far as I can ascertain from the text of Attems’s monograph, the only examples he 
has seen of the species he described as Fontaria tepancca, Sauss., were those in the 
Hamburg Museum which Karsch described as Fontaria angelus. 1am unable to say 
certainly whether his determination of these specimens as conspecific with those that 
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