Characters in Paratrombium — Newell 
minutely barbed at magnifications of 600 X 
(Fig. 76). Beginning at .32 and extending an- 
teriorly is a deep furrow, reaching to the level 
of about .08; beyond this level are three setae 
as in the previous species. Narrowest point 
of scutum at .22 to .27. Punctate cuticle ex- 
tending very nearly to the posterior end of 
the scutum, which is not markedly swollen 
as in P. bidactylus , and the pigmented cuticle 
ends in front of the depression in the end of 
the crista. In the portion of the scutum be- 
tween .25 and .68 of the specimen examined, 
there were 30 setae, 15 on each side (P. b.: 
31 setae here, in the one specimen). Crista 
metopica tapering somewhat more gradually 
behind area sensilligera than in preceding 
species. Ocular plates and dorsal hystero- 
somal setae as in P. bidactylus. 
Ventral surface of the body showing no 
significant differences from P. bidactylus , ex- 
cept for a slightly more sparse vestiture of the 
coxae and genital sclerites. Genital sclerites 
bearing 39 and 37 setae (P. £..'48-55), para- 
genital sclerites bearing 26 and 29 setae (P. b.: 
about 55 on each side). The form of these 
setae is essentially identical in the two spe- 
cies, however. Gnathosoma in ventral view 
resembling that of P. bidactylus , but slightly 
larger; rostrum not reaching to distiventral 
margin of femur (in P. bidactylus the rostrum 
extends to a point about half way between 
the distiventral and distidorsal margins of 
the segment). 
Chelicerae virtually identical with those of 
P. bidactylus , except that the row of denticles 
is straight throughout its length, whereas in 
the preceding species it is sharply deflected 
about the middle. Palpi virtually identical in 
general size and form with those of the pre- 
ceding species. Tibia with large unidentate 
odontus but without paradont. One feebly 
developed ctenidium present, consisting of 
about four setae somewhat longer, heavier, 
and smoother than the others, extending 
along the anteroventral margin at the inser- 
tion of the tarsus. Eupathidia of tarsus ex- 
tending from .68d to .95^, solenidion at .80 
367 
to .85 p. The eupathidia of the palpal tarsus of 
this species are noticeably more numerous 
(17-19) than in P. bidactylus which has only 
11 on each tarsus. With such a difference as 
this, it is doubtful that study of larger num- 
bers of individuals would show much over- 
lapping in this character. 
Tarsus I 423 /x long, 144-149 m high, 
length/height 2.84-2.94; tibia I 261-266 /jl 
long, tarsus I/tibia I 1.59-1.62 (single 
specimen). 
larva: Idiosoma (Figs. 61, 62) 356 to 383 /x 
long, 189 to 203 m wide, length/width 1.87 
to 1.92; average 374 /jl by 197 /jl , length/ 
width 1.88 (five unengorged larvae). Scutum 
essentially as in Paratrombium bidactylus; pro- 
sensillar setae completely smooth, somewhat 
spindle-shaped, with thickest portion about 
one-fourth of the way out on the shaft. An- 
terior portion of scutum striate, posterior 
portion densely and uniformly punctate. 
Sensilla appearing smooth at low magnifica- 
tions but faintly pectinate under higher mag- 
nifications. Ocular plates bicorneate, the an- 
terior cornea larger than the posterior. Post- 
scutum bearing four setae in a transverse row. 
(In some individuals of P. bidactylus , one of 
the setae of the postscutum may be dupli- 
cated, but in these cases the placement of the 
supernumerary seta is quite different since it 
is not aligned with the two normal setae.) 
Remaining dorsal and marginal setae identical 
in number and position with those of P. 
bidactylus , so that there is a total of 26; venter 
with 6 peripectinate postcoxal setae, making 
a total of 32 postcoxal and postscutal setae. 
Except for the setae of the postscutum, all of 
the setae are borne on individual punctate 
sclerites. Membranous cuticle faintly striate, 
but the striae do not make any striking pat- 
tern. Ventral surface showing no significant 
difference from P. bidactylus. One dissection 
provided considerable insight into the struc- 
ture of the so-called urstigma (or "urpore”). 
In Figure 73 (dorsal view) the urstigma is 
seen to consist of an elliptical cavity or ring, 
with no opening whatever on the ventral sur- 
