Johnstonianidae — Newell 
423 
pair of minute structures like those found in 
C. distans which may represent the vestiges of 
the deutorostral setae. Including the proto- 
rostrals and tritorostrals the rostrum bears 10 
to 16 setae. Chelicerae (Fig. 60) of standard 
form, tarsus heavily sclerotized, appearing 
smooth at low magnification but with 20 to 
30 extremely minute teeth visible at mag- 
nifications of 250 x or higher. Trochanter of 
palp (Fig. 61) with fenestral membrane on 
anterior aspect, setae absent; femur with about 
12 smooth straight slender setae. Two of the 
normal setae on the femur of the palp appear 
to occupy a characteristic posterior position, 
isolated from the remaining 10 setae of the 
segment. Patella with about 9 setae, tibia with 
8 smooth slender setae plus the large clawlike 
unidentate distal seta, and a shorter spiniform 
seta near its base. Tarsus of palp with three 
rather heavy normal setae along dorsal margin 
(Figs. 58, 59), two heavy eupathids distally, 
and a single solenidion posteriorly. 
male: Resembling female in all essential 
respects noted above except for structure of 
genital area. Genital sclerites and paragenital 
sclerites as in female, but with slightly fewer 
setae in most cases. Penis of rather character- 
istic form, with three elongate apodemes. 
Genital acetabula numbering three pairs. Anal 
sclerites also as in female. 
Chaetotaxy of legs approximately as shown 
in table (s = solenidia, e = eupathidia, f = 
famulus, v = vestigial setae, c = companion 
setae, n = normal setae, m = many). 
Basifemur I with about 20 to 25 normal 
setae. Vestigial setae absent; eupathidia found 
only on the tarsi. Tarsus I with famulus at 
0.89 pd and with two solenidia 2 on posterior 
aspect (only one in some cases). Tarsus II 
with s 2 at about 0.64 pd, and with a spikelike 
famulus at 0.64 to O.l'dpd. Eupathidia extend- 
tr 
bf 
tf 
pa 
n 
n 
S3 
s 3 
s 4 
I 
4-5 
23 
11 
31 
2-3 
II 
4-5 
15-16 
6 
10 
1 
III 
6 
11-13 
4 
8 
2 
IV 
12 
9-10 
4 
6 
0 
ing from 0.55^ to 0.95 d. Eupathidia of tarsus 
I extending from 0.49^ to 0.85 d. Tarsus I also 
with numerous Si and a number of smaller 
solenidia intermediate in size and form be- 
tween Si and S3, and assigned in the table to 
type s 4 . There appears to be fairly complete 
intergradation between s 4 and Si as in the case 
of C. distans. 
type locality: About 4 miles north of 
Tonasket, Okanogan County, Washington, 
from border of small permanent pond. August 
14, 1952. Collected by the writer. This spe- 
cies has not been found elsewhere, and may 
be a more northerly form, whose principal 
range extends into British Columbia. 
remarks: This species is very similar to 
Centrotrombidium distans new species, but dif- 
fers consistently in the close approximation 
of s 2 and the famulus of tarsus II (hence the 
specific name). It also differs in having con- 
siderably fewer solenidia on the legs (approxi- 
mately 125 compared with 200 in C. distans). 
The difference is largely due to the discrep- 
ancy in the number of s 3 (about 80 in C. 
approximation, compared with 160 in C. dis- 
tans ); the other solenidial types are present in 
approximately equal numbers in the two spe- 
cies. Other differences are in the form of the 
posterior end of the scutum, and the form of 
the ocular plate as indicated in the foregoing 
description. 
Centrotrombidium hadroseta new species 
female: A single specimen of this form was 
found at the type locality of C. approximatum. 
It is closely related to C. distans from which it 
differs in only very minor respects. Body of 
same form as C. distans , 962 \x long, 650 \i 
wide, length/width 1.48. Scutum (Fig. 63) 
essentially as in C. distans , except that the 
setae in front of the sensilla appear to be 
ti ta 
S3 
S4 
Sl 
s 2 
S3 
s 4 
e 
f 
7-9 
1 
11 
2,1 
0 
7 
m 
1 
6 
1 
11 
1 
0 
0 
m 
1 
4 
1 
0 
0 
2 
3 
8 
0 
4-5 
0 
0 
0 
1 
1,2 
1,0 
0 
