48 DIPLOPODA. 
The following species are unknown to me:— 
8. Platydesmus moreleti. 
Piestodesmus moreletii, Lucas, Rev. et Mag. Zool. 1849, p. 599, t. 17. figs. 1-1 d*. 
Colour: head fuscous, antenne testaceous; first tergal plate fuscous, the remainder fuscous with reddish 
keels ; legs testaceous. 
Head with prominent eyes. Antenne short and thick. Jirst tergal plate large, its anterior border produced 
into a right and left shelf-like plate, forming a straight, transverse, anterior border and separated from 
each other by a narrow longitudinal triangular notch. Body broad, less than three times as long as wide 
(14:5), the two rows of tubercles on the terga subequal in extent, both passing nearly to the distal 
extremities of the keels. Posterior tergal plate narrow and piriform, pointed posteriorly. Sterna of mid- 
region of body wide, exceeding in width the length of the two proximal segments of the legs. Number 
of segments 41. 
Total length 13°5-14, width 4:5-5 millim., 
Hab. Mexico, Tabasco (under stones) (Morelet 1). 
9. Platydesmus polydesmoides. 
Platydesmus polydesmoides, Lucas, Ann. Soc. Ent. Fr. 1843, p. 52, t. 3. 1. figg. 1-8 *. 
Colour : head fuscous above, pale below; antenne pale ; body yellowish, spotted with reddish-brown upon the 
sides, clear yellow in the median area. 
Body rather narrow, about five times as long as wide. yes present. First tergal plate widely emarginate in 
front, leaving the head entirely uncovered. Posterior row of tubercles on terga only extending to base 
of keels. Last tergal plate narrowly piriform, surpassed posteriorly by the keels of the preceding segment. 
Number of segments 44, 
Length 21, width 4 millim. 
Hab. GUATEMALA}. 
P. polydesmoides is nearest to P. triangulifer and P. lineatus, but, so far as 
coloration is concerned, apparently differs from both. Neither description nor figure 
is sufficiently detailed to admit of its inclusion in the key to the species (anted, p. 44). 
Humbert and de Saussure also record it from Cordova, Mexico, but whether 
rightly or wrongly it is impossible to decide. 
10. Platydesmus mexicanus. 
Platydesmus mexicanus, Humb. et Sauss. Rev. et Mag. Zool. 1869, p. 156°; Miss. Sci. Mex., 
Myr. p. 103, t. 2. figg. 5, 5 d-e’. 
Colour deep brown, keels not pale, except in young; median dorsal line pale and expanding at intervals into 
seven yellowish triangular patches, as in P. triangulifer and P. marmoreus, the keel on each side opposite 
the posterior angle of the patches also yellow; antenne yellow. 
Head with eyes. Body very broad, only a little more than four times as long as wide. First tergal plate 
emarginate in front, without any lamine, leaving the head entirely uncovered and the anterior edge of 
the median or cylindrical part of the segment visible. Posterior row of tubercles on segments not 
extending on to keels. Last tergite narrowly piriform, overlapped posteriorly by the keels of preceding 
segment. Number of segments in adult varying from 41-60. 
Total length of adult 26, width 6 millim. 
Hab. Muxico, Kastern Cordillera ', Sierra de Agua °. 
