1968] 
Coyle — Spider Genus Atypoides 
183 
Most of the sample P specimens, both from M> and a few other 
individuals have AL spinnerets which are reduced to nearly imper- 
ceptable swellings marked by two or three crooked setae. Other 
specimens have AL spinnerets intermediate in size between these and 
those in samples N and O which are usually 1/6 to 1/5 as long as 
the PM spinnerets. 
Females. As in the male sample comparisons, M is the most 
divergent and P the next most divergent sample of females. Wide 
overlap exists among all four population samples in almost every 
character. For measurements and meristic characters, the greatest 
interpopulation “distances” show up in ICTR (Fig. 64), IVCTP, 
IVCTR, and CT (Fig. 65) in each of which sample M is divergent. 
The only ratios with strong geographic variation are CT/ICTR 
(Fig. 66), which produces a gap between sample M and the others, 
and IVTL/CL (Fig. 67) and IVML/CL both of which separate 
sample P somewhat from the other samples. 
The setation of the carapace and chelicerae of females (and males) 
from M and from Ney Springs, Siskiyou Co., Calif., is sparcer than 
on most specimens from other localities. The dorsal protuberance 
of the chelicerae in side view is slightly higher and less broadly 
rounded in most females of sample M. The AL spinnerets of several 
specimens from P and one from M are greatly reduced as described 
above for the males. Sample O has the highest mean AL spinneret 
length, N and M the next highest. 
The seminal receptacles exhibit wide variation in shape. Samples 
N and O and a small sample from Crater Lake Natl. Park have 
widely overlapping ranges, with stalks usually quite sinuous (Figs. 
90-92). Population sample P differs markedly from these samples, 
with nearly non-sinuous to slightly sinuous and short stalks (Fig. 94). 
M also differs, usually with nearly non-sinuous and stout stalks 
(Fig. 93). 
discussion. These patterns of geographic variation may be the 
result of reduced interpopulation gene flow at the periphery of the 
species range and consequent divergence of certain peripheral popula- 
tions (M and P ) . Population M appears to be near the northwest- 
ern periphery of the species range and is much lower in elevation and 
in a somewhat different habitat than the other three population 
samples. Population P is near the southern edge of the species range. 
Larger sample sizes (particularly of males) and geographically in- 
termediate samples are needed to clarify the status of these two pop- 
ulations. The possibility that isolating mechanisms have evolved 
