46 DIPLOPODA. 
2. Platydesmus analis, sp.n. (Tab. IV. figg. 3, 3 a-g.) 
Colour marbled ; dorsal surface blackish in the middle, yellowish laterally, with a yellow spot in the centre 
of the fourteenth, twenty-second, thirty-second, fortieth, forty-sixth, and fiftieth segments ; the keels of 
these same segments yellow ; the rest of the keels deep brown with a yellow basal spot separated by a 
dark area from the yellow lateral portion of the dorsal surface ; at the posterior end of the body the 
keels and median area are yellower than on the anterior segments ; head, antenne, and last tergal plate 
infuscate; legs and sterna and infero-lateral area pale. 
Body long and narrow, about nine times as long as wide (28:3). First tergite widely emarginate, with 
numerous granules. Both rows of tubercles on segments extending almost to extremity of keels and 
accompanied by others. Last tergal plate wide, its posterior extremity truncated and scarcely or only a 
little surpassed by the keels of the preceding segment. Sterna of mid-region nearly as wide as two 
basal segments. Number of segments 53-60. 
Total length 28, width 3 millim. 
Hab. GUATEMALA, t Guatemala city (StoJ/). 
8. Platydesmus hirudo, sp. n. (Tab. IV. figg. 2, 2a-e; Tab. V. fig. 1.) 
@. Colour black, with a narrow yellow dorsal line and yellow keels; head infuscate, last tergal plate blackish ; 
ventral surface and legs yellowish brown. 
Body moderately broad, about or almost five times’ as long as wide (22:4°5). Head hairy, punctured, with 
two distinct ocelli; antenne moderately long, incrassate, the segments narrowed or constricted at the 
‘base. Hirst tergite with its anterior border scarcely produced, widely emarginate, and only lightly convex 
on each side of the middle line, leaving the summit of the head entirely uncovered; with two rows of 
tubercles, its median area not quite twice as long as the elevated median area of the second. Of the two 
rows of tubercles on the rest of the segments, the anterior consists of from about twelve to fourteen and 
extends along the median line of the keels; the posterior is much shorter, consisting of only five or six 
and scarcely reaching the keel. -Sterne of the mid-region of the body rather shorter transversely than 
the length of the coxa and trochanter of the adjacent appendage. Last tergal plate oval, narrow behind, 
narrower than the keels of the preceding tergite, which project beyond it posteriorly ; furnished with six 
setiferous papille, the outer on each side remote from the rest. 
Total length of large specimen, 9 , 27, width 5°5 millim.; ¢, 20, width 4 millim. 
Hab. Mexico, Omilteme in Guerrero (H. H. Smith). 
4. Platydesmus lineatus, sp. n. (Tab. IV. figg. 5, 5 a-g.) 
Colour as in the preceding species, but with median dorsal stripe not so distinct, not evenly thick, with sinuous 
edge, expanding here and there in a way suggestive of what is seen in P. triangulifer. 
Body relatively narrow and long, about six or seven times as long as wide (20:3). Head completely 
uncovered by the first tergite, which is widely emarginate but has its angles more rounded than in 
P.hirudo. Segments with two rows of tubercles, the anterior row extending to lateral margin of keel, the 
posterior consisting of about six on each side not passing on to keel. Sterna in mid-region of body a 
little narrower than length of two basal segments of legs (excl. trochanter), about as wide or a little 
wider than twice the length of the basal segment. Last tergal plate narrower than keels of preceding 
segment, which overlap it posteriorly. Number of segments 44-49. 
Total length 20, width 3 millim. 
Hab. Mexico, Volcan de Orizaba (Mus. Brit.). 
5. Platydesmus mesomelas, sp. n. (Tab. V. fig. 2.) 
Colour as in P. hirudo, but without any yellow median dorsal stripe. 
Body broad, about four times as long as wide (20:5). Head and antenne as in P. hirudo, but the first tergal 
plate differently shaped, being much larger owing to the expansion of its anterior border over the head so 
