80 DIPLOPODA. 
enumerated in the above-given analytical Key. Three small female specimens from 
Ciudad in Durango, Mexico (Forrer), represent the same or a closely allied species. 
The number of segments varies from 44 to 47, and the length of the largest is 
55 mm. and the width 7 mm. 
7. Spirobolus monticola, sp. n. 
Colour ferrugineo-olivaceous, the first tergal plate with a reddish-yellow band running along the dorsal portion 
of its anterior and posterior margin, a similar band on the dorsal portion of the posterior margin of the 
rest of the segments. 
The head marked below with abbreviated vertical sulci. The first tergal plate with the anterior border of 
the lateral portion widely emarginate, the posterior border evenly convex. The second with its posterior 
angle rounded and obtuse, the anterior angle rounded and produced more forwards. The rest of the 
tergal plates distinctly punctulate and striolate throughout, laterally striate up to the pores, the 
transverse sulcus very feeble, represented by a slight depression; the dorsum marked by a transverse 
sulcus, which is continued from the level of the pore in front of the true sulcus. Anal segment small ; 
valves small, with their compressed margins projecting far beyond the apex of the tergum. 
Number of segments 45. Measurements: length 87 millim.; width 11°3, of first segment 8°5, of anal 
tergite 6°8; height of anal segment 7, of body 10. 
Hab. Mexico, Omilteme in Guerrero 8000 feet (H. H. Smith). 
This species seems to resemble S. mystecus in the form of its first tergal plate, but 
the second segment is much less strongly produced inferiorly. It is also considerably 
stouter in build and more closely sculptured than the specimen from San Andres Tuxtla 
described below; but in this respect S. monticola resembles Saussure’s examples of 
S. mystecus. 
In the form of the inferior portion of the second segment, S. mystecus occupies 
a position intermediate between S. tepanecus and S. monticola. 
8. Spirobolus tepanecus. 
Julus tepanecus, Sauss. Linn. Ent. xiii. p. 8332 (1859) ; id. Mém. Soc. Phys. Geneve, xv. p. 568, 
t. 5. fig. 35 (1860). 
Spirobolus tepanecus, Sauss. et Humb. Miss. Sci. Mex., Myr. pp. 88, 177 (1872). 
Colour (in alcohol) olivaceous or ochraceo-olivaceous ; the posterior border of the segments fusco-olivaceous ; 
legs, antennz, and lower surface ochraceous. 
Head punctulate, with a complete median sulcus, the labral region roughened with punctures and grooves ; 
eyes composed of about 26 ocelli arranged in four transverse rows. The first tergal plate laterally 
narrowed, the antero-lateral border nearly straight, the postero-lateral border with a slight notch above 
the angle. The second segment with the posterior angle of the inferior portion rounded and obtuse, the 
anterior angle strongly produced, the process forming a bluntly acute angle; the posterior border lightly 
notched, the base of the process bearing a deep fossa. The rest of the segments finely striolate and 
punctulate. The transverse sulcus strongly developed, bifurcating at the pore and extending over the 
dorsum as two parallel grooves, of which the posterior is the stronger ; a weak longitudinal sulcus running 
backwards from the pore. The lateral surface striate nearly up to the pore; the posterior border of the 
lateral and inferior surface in the hinder part of the body finely serrate. The anal tergal plate distinctly 
but obtusely angled above, the margin of the valves projecting considerably beyond its apex; the sternal 
plate angular. 
In the male the coxe of the legs from the fourth to the seventh pairs are furnished with a lamelliform pro- 
longation which is apically two-pointed. 
