148 DIPLOPODA. 
b'. Anal sternal plate semicircular ; area between the setiferous tubercles 
convexly produced . . . . ee ee ee : - « . .  POLYLEPISCUS. 
a’. Dorsal surface of segments smooth ; phallopod more complicated, subdivided, 
the seminal stile guarded by wide sheath-like accessory branches. . . . APHELIDESMUs. 
AMPLINUS. 
Polydesmus (Paradesmus), Saussure, Liun. Ent. xiii. p. 325 (1859) (in part.: Div. i1.); Mém. 
Soc. Phys. Genéve, xv. p. 292 (1860) (in part.: Section i.). 
Polydesmus (Pachyurus), Humbert & Saussure, Verh. zool.-bot. Ges. Wien, xix. p. 673 (1869) 
(in part.) ; Mém. Sci. Mex., Myr. p. 27 (1872). 
Polylepis, Bollman, Bull. U.S. Nat. Mus. 46, pp. 160 & 197 (1893) (for Pachyurus, preoccupied). 
Pachyurus (Amplinus), Attems, Denk. Akad, Wien, lxviii. p. 281 (1900) (misprinted Amphinus). 
Pachyurus, Brélemann & Carl (in part.). 
Antenne short, segments 2-6 not very unequal in length, subequal or gradually increasing to the sixth; 
area between them narrow and marked with a A-shaped sulcus, the upper limb of which is the down- 
ward continuation of the deep frontal sulcus, the two lower limbs passing into the antennal sockets, 
the area below the fork and above it on each side swollen, rounded, smooth, and shining. First tergal 
plate wider than the head and nearly or quite as wide as the second, produced laterally into angular 
cariniform laminee. Dorsal surface of all the segments, with the occasional exception of the first or a 
few more of the anterior segments, sculptured, the sculpturing consisting of three definite rows of 
polygonal areas, sometimes themselves granular or tubercular, or of about four rows of rounded or 
elongate, large, smooth tubercles, often broken up by smaller ones. Lateral borders of the sels 
thickened. Pores lodged in depressions of the thickening, and usually looking outwards, sometimes 
more or less upwards; cylindrical area of segments quite smooth, lateral area granular. Sterna 
smooth, about as wide as long, transversely and longitudinally sulcate. Anal teryal plate ending in a 
broad subquadrate caudal process, with subparallel lateral borders, straight or lightly convex posterior 
border, as wide behind as in front, or approximately so. Anal sternal plate with posterior border wide, 
emarginate or nearly straight from side to side, when emarginate there is a distinct bluntly rounded 
setiferous prominence on each side. Legs with third segment slightly or markedly longer than sixth, 
which is much longer than the fifth, the latter a little longer than the fourth. Phallopods with distal 
segment moderately long, projecting forwards parallel to each other, and ending in two, rarely in three 
prongs, the inferior prong being the seminal stile. 
Type, A. kalonotus, Attems. 
Distribution. Central and northern parts of South America. 
Under the name Pachyurus, Humbert and Saussure included originally P. klugi, 
Brandt, from Central America, P. margaritaceus and P. squamatus, Koch, and 
P. granosus, and pointed out that the latter from the Moluccas differed from the three 
others in having the first tergal shield only as wide as the head and much narrower 
than the second. ‘These characters, as Attems has shown, hold good, so far asis known, 
as a distinguishing feature between the Oriental and American species. ‘The first 
author who definitely fixed the type of Polylepis, which was so named by Bollman 
because Pachyurus was preoccupied, was Silvestri, who in 1896 [Ann. Mus. Genova, 
(2) xvi. p. 190] selected the Moluccan P. granosus, thus assigning the name 
Polylepis to the Oriental species with narrow first tergal plate. Overlooking this fact, 
I subsequently gave the name Paradesmorhachis to a species, P. solomonis, from the 
