8 CHILOPODA. 
9. With the fourteenth and fifteenth pairs of legs of normal form; claw of the generative forceps stout, not 
long, and undivided; two basal spurs on each side, of which the external is considerably longer and 
stouter than the internal. 
Length up to 26 millim.; average length about 21 millim., with antenne measuring about 11:5. In one 
specimen, measuring 26 millim., the antenne are not more than half the length of the body. 
In young specimens (i. ¢. males in which the fourteenth and fifteenth pairs of legs are unmodified, and females 
in which the generative forceps is only half-formed) the coxal pores are 3, 2, 2, 2. 
Hab. Mexico, Omilteme in Guerrero 7000 to 9000 feet (H. H. Smith). 
Obtained under rotting wood &c. about the clearings and neighbouring forest 
(H. H. Smith). 
The males of this species may be easily recognized from those of L. godmani by the 
difference in the form of their posterior legs. But the females are very hard to 
determine. Possibly the two species may prove to be identical ; in which case we shall 
have an interesting instance of dimorphism in the males. I think, however, that, 
provisionally at least, it is wiser to regard the two as distinct, at all events until a 
larger series of the females are forthcoming for examination. 
In the case of females not associated with males, I have referred all those from 
Omilteme to Z. salvini, and those from Amula to L. godmani. 
6. Lithobius vulcani, sp. n. (Tab. I. figg. 8, 8a, 8 6.) 
Colour castaneous. 
Head weakly punctured ; frontal plate distinct, with conspicuous median groove. 
Eyes composed of about 9 ocelli, 1+1, 3, 3. 
Antenne of moderate length, composed of 41 segments. 
Coxal plate of mawillipedes with anterior edge lightly emarginate, armed with 3+3 evenly spaced teeth, 
whereof the external is slender and has the appearance of being a movable spinule. 
Terga smooth: ninth, eleventh, and thirteenth with produced angles; the fourteenth posteriorly emarginate, 
the rest of the posterior borders straight. 
Legs: spine-armature of first, 0, 0, 0, 1, 15 the fifteenth leg a little longer than fourteenth, armed below with 
0, 1, 38, 3, 1 spines, claw double ; the coxal pores uniserial, small, circular, 4, 4, 4, 3. 
g. Legs of the fourteenth pair with the tibia much thicker than the tarsal segments, and thicker in the 
middle than at the two ends; the tibia of the anal leg also slightly thickened, a little flattened posteriorly 
on its inner side, and from the middle of the flattened area there rises a low crest, which terminates 
abruptly behind. 
Generative appendages represented by two short, rounded processes. 
Length 17 millim. 
Hab. GuateMata, Volcan de Agua (Stoll). 
In the same bottle as that which contained the above described male there was a 
female measuring 19 millim., with 36 antennal segments, 5, 6, 6, 5 coxal pores, two 
long subequal spurs, and a simple claw on the generative forceps, but otherwise 
agreeing with the typical male. Another smaller specimen, a male, which may be an 
immature form of the one described, has only 32 antennal segments, and the anal legs 
unmodified. | 
In its male sexual features, 7. e. in having the tibie of the fourteenth and fifteenth 
