SPIROBOLUS. 79 
The posterior angle of the second segment rounded and obtuse; the anterior angle also rounded and 
slightly produced. The rest of the segments striolate and somewhat coarsely punctured, especially along 
the groove where the transverse sulcus runs, the lateral surface closely but feebly striate, and posteriorly 
serrulate up to the pore; the transverse sulcus either entirely obsolete above or nearly so; not bifurcating 
above the pore, Anal segment large; the tergal plate wide and obtusely angled posteriorly, not quite 
covering the valves, which have lightly compressed margins; sternal plate with convex border. 
Male slenderer, with the coxe of the first and second legs unmodified ; those of the third produced into a soft 
flexible short process; those of the fourth with a shorter blunter process, and of the fifth to the seventh 
unmodified. 
Copulatory apparatus with the sternal plate strongly curved, concave above, deeper than in the other species 
and mesially impressed ; the anterior lamine of the coleopods wider laterally than mesially, where they 
are punctured, and produced into a short downwardly directed process; the posterior lamina with its 
inferior angle strongly curved outwards. The phallopod with its proximal segment in the form of a long 
slender rod; the distal segment short, but longer than wide, laminate, externally geniculate at its base, 
its outer margin convex and finely serrate. 
Number of segments 41 to 46. Length of large female specimen about 73 millim.; median width 8-7; 
width of first segment 7:7, of last 6, height of latter 6-2. 
Hab. Mexico, Omilteme in Guerrero 8000 feet (H. H. Smith). 
Apart from the secondary sexual characters of the male, this species differs from all 
the Central-American species known to me in the coarse and very distinct punc- 
tuation of the posterior area of the segments. In this particular 8. fossulifer seems to 
come nearest to S. reptans, Porat, from Guanajuato (cf. infra) ; but is doubtless distinct, 
for Porat described the second segment of S. reptans as being scarcely produced below 
the level of the inferior angle of the first. 
6. Spirobolus amulensis, sp. n. 
Colour (in alcohol): head, legs, antenne, first and anal segments olivaceous; anterior and posterior borders of 
first and posterior borders of the other segments ferruginous. 
Head smooth ; 6 labral pores ; sulcus mesially incomplete. Anterior border of lateral portion of first tergal 
plate very slightly emarginate ; posterior border evenly convex. ‘The posterior angle of the second segment 
convex and evenly rounded; the anterior angle scarcely at all produced in front, forming a continuous 
line with the anterior border of the segment. The rest of the segments dorsally punctulate, striolate, 
laterally weakly striate up to or nearly up to the pore, those at the hinder end of the body laterally 
serrulate ; the transverse sulcus manifest, as high as the pore, not bifurcating above it; the anterior 
portion of the segments slightly but distinctly elevated, being separated from the posterior portion by a 
shallow depression, this difference of level being especially well marked in the anterior half of the body. 
Anal segment with tergal plate produced into a widely rounded process covering the summit of the valves, 
which are very lightly compressed ; sternal plate obtusely triangular. 
Number of segments 48. Length about 100 millim.; width 10, of first segment 8:5, of anal segment 6; 
height of anal segment 6°5, of body 9°8. 
Hab. Mexico, Amula in Guerrero (4. H. Smith). 
This species may be distinguished from the rest here described by the smooth 
elevated ridge which crosses the anterior segments from side to side. It differs further 
from S. tepanecus, S. mystecus, and S. monticola in that the transverse sulcus does 
not bifurcate above the pore. Moreover, the anterior angle of the second segment is 
scarcely at all produced. From &. fossulifer it may be separated by the characters 
