204 DIPLOPODA. 
Saussure named tepanecus is correct or not. The description is too inadequate to 
supply data for such a conclusion, since it applies to many of the Central-American 
species of this genus. It may be noted, however, that Attems does not draw attention 
to the sexual differences pointed out by Saussure. Moreover, the measurements he 
gives suggest that the co-types of R. angelus are narrower than the type (¢) of 
R. tepanecus from Cordova and than the females from Moyoapan and Santa Cruz, 
near Orizaba, which Saussure and Humbert subsequently identified as that species. 
The male of R. angelus, for example, is 42 mm. long and 8°5 wide; while the male 
of R. tevanecus was 40 wm. long and 10 mm. wide. This fact, coupled with the 
inadequacy of the description of R. angelus, and with the circumstance that LR. tepanecus 
was not recorded from Puebla, induces me to keep the two species distinct provisionally, 
lest R. angelus be wrongly lost sight of as a synonym and until the phallopod of 
R. tepanecus be described and compared with that of R. angelus, the structure of which . 
has been partially made known by Attems. In being straight and gradually attenuated, 
this phallopod seems to résemble that of R. attemsi, but certainly differs in the 
greater thickness of the principal branch and the sinuous curvature of its edges when 
seen from the side. In these latter respects it somewhat calls to mind the phallopod 
of R. pusillus, but unmistakably differs, according to Attems’s description, in having 
the principal branch straight and not inclined distally. 
Attems has also recorded as R. tepanecus a species represented by specimens 
in the Hamburg Museum from La Joya, Mexico, and from Soconusco, Chiapas 
(Mt. Mus. Hamb. xviii. p. 85, 1901). Since neither of these localities is mentioned 
in his monograph of 1900 under the heading Fontaria tepaneca, it is impossible to 
say whether the specimens are specifically identical with /. angelus or not. 
17. Rhysodesmus consobrinus. 
Polydesmus (Fontaria) consobrinus, Sauss. Linn. Ent. xiii. p. 322 (1859) *; Mém. Soc. Phys. Genéve, 
xv. p. 317, t. 2. fig. 13 (1860) *; Sauss. & Humb. Miss. Sci. Mex., Myr. p. 387 (1872) °. 
Colour unknown ; greyish or whitish. 
9. Like that of R. otomitus, but the dorsal surface slightly more convex and the eels a little more sloping, 
with the marginal thickening more linear, those which bear the pores being scarcely swollen. Pores small, 
not lodged in small pits, opening behind the middle of the lateral border, even on the 7th segment; and 
the spine on the legs stronger. 
¢. Dorsal surface less convex, lateral border of the heels straighter, their posterior angles less obtuse, 
rectangular on the segments in the anterior half of the body and not obtuse as in the @. In the median 
and posterior segments the keels are horizontal, with their posterior angles acute and triangularly 
prolonged, the posterior border forming a distinct angle and not an even curve with that of the median 
area of the segments ; posterior angle of segments 16 to 19 very sharp. 
Length 31 millim., width about 7. 
Hab. Mexico, the colder parts of the plateau (Anahuac, Volcan de Orizaba, &c.)'~*. 
Said to be easily distinguishable from &. fraternus by its less convex shape, the 
female of R. consobrinus being even flatter than the male of R. fraternus. 
