RHYSODESMUS., 199 
the tubercles angled. Sternal plates only lightly emarginate, more strongly so posteriorly, like those 
of R. stolla. 
Length, 2, 42 millim., width 9; length of antenne 6 millim. 
Hab. Guatemaa, Zapote, Pacific slope (Champion). 
7. Rhysodesmus flavocinctus, sp.n. (Tab. XV. figg. 6, 6a.) 
3. Colour: transversely banded with brown and yellow, the anterior half of the dorsal area of the meta- 
zonites and the prozonites being dark brown, the posterior half of the metazonites yellow-brown and 
rather darker than the keels and caudal processes, which are pale yellow; first tergal plate brownish 
only in the middle ; head brown above, paler below ; antenne brownish yellow; legs yellowish, a little 
darker than the sternal areas. 
Antenne short ; head equal to segments 2-4+ half of 5 ( ¢) or to 2-5+half of 6 (92). 
Body robust. Keels well developed, depressed, and almost following the slope of the dorsal area of the 
metazonites; those of the segments 1 to + much less narrowed laterally than in the three preceding 
species, the antero-lateral border of the lst being evenly convex, the anterior angle of the 2nd and 
3rd more rectangularly and less obtusely rounded; the anterior border of the succeeding keels more 
strongly produced, the greatest convexity of the crest being close to the anterior angle, which is rounded, 
the posterior angle scarcely produced ; the posterior border very lightly convex or nearly straight, lateral 
border evenly thickened, not abruptly thickened in front of the pore as in R. stolli, Pores not so far 
forwards as in RA. stolli and R. tabascensis, not in front of the middle of the keel, and lying well in 
the posterior half in the posterior portion of the body. Keels of J9th segment small, sometimes 
surpassed by those of the 18th. Dorsal surface smooth, with a few small tubercles near the base 
of the keels. Anal sternal plate with a small median dentiform process between the tubercles. Sternal 
areas and legs practically as in A. stol. Ridge between the zonites continued right round, taking an 
abrupt bend in front of the base of the keel, but not quite continuous with the ridge along the anterior 
border of the keels. 
Phallopods stout, with their distal extremity geniculate, turned obliquely inwards and forwards and upwards ; 
the auxiliary branch rising just behind the middle of the upper (adoral) aspect of the organ and directed 
obliquely forwards and upwards with a sinuous curve. 
Length, ¢, about 28 millim., width 7; length of antenne 6 millim. 
= », » sl, » 8; ” ” 5) ” 
Hab. Mexico, Amula in Guerrero 6000 feet (7. H. Smith). 
8. Rhysodesmus godmani, sp.n. (Tab. XV. figg. 4-4 d.) 
Colour chocolate-brown ; keels brown, except their anterior portion, which is clouded with brown; head 
brown ; antennz brown and darker than the legs, which, like the ventral surface, are pale yellowish ; 
dorsal area of prozonites as dark as the adjoining area of the metazonite and darker than their ventral 
portion. 
Head with frontal sulcus ending inferiorly in a distinct depression. Antenne long, in male about equal to the 
width of the body across the keels, with segments 2+3+44 equalling width of head; in female rather 
shorter. first tergal plate with an anterior transverse depression, rather widely rounded lateral border, 
with the posterior angle slightly obtuse; posterior border sinuous, mesially emarginate, very lightly 
curved laterally. Body not compact, but like that of typical members of the Chelodesmine. eels 
separated, large, and nearly horizontal; their anterior border rather strongly curved at the base; 
anterior angle widely convex; posterior border nearly straight, but shouldered at the base and 
defined by a distinct notch ; their posterior angle rectangular, becoming gradually more and more acute 
(but never sharp or spiniform) from the 15th to the 18th; those of the 19th blunt; a few tubercles on 
their upper side. Metazonites very finely striolate, separated in front from the prozonite by a decided 
groove, bordered in front by the ridge which passes in front of the keel without any marked alteration 
of direction : thus the metazonites and prozonites do not form a continuous surface. Anal sternal plate 
with an angular process between the setiferous tubercles. Sterna moderately high, not flat in front ; 
