1974 ] 
Coyle — Genus Aliatypus 
459 
A. gnomus; smaller CL/PTSR and IFL/IVFL (Table 2) than in 
A. calif ornicus ; smaller IFL/IVFL and fewer IMS (Table 2) than 
in A. janus ; fewer IMS and smaller CL/ITL (Table 2) than in 
A. isolatus. Because of its small widely spaced posterior sigilla 
(Fig. 68) and proportionately long tibia IV, A. aquilonius is easily 
separated from the rest of the species by the following characters 
(Table 2): CL/IVTL, CL/PSS, CL/PSL, SW/PSS, SW/PSL, 
and PSL/PSS. 
Description. See Tables 1-3. 
Males: Carapace. Thoracic groove a deep longitudinal groove or 
a deep rounded pit. Postocular setae form a relatively short and 
narrow longitudinal band. Sternum. Fig. 57. Posterior sigilla faint, 
small, and far apart. Pedipalp. Figs. 81, 106. Distal half of tibia 
ventrally moderately swollen. Embolus base distant from ICS base. 
Palpus tipped with weakly sclerotized finger-like extension. Inner 
(concave) edge of OCS smooth. Leg I. Tibia and metatarsus with 
most of ventral macrosetae attenuate ; background setae long, slender, 
erect, and rather sparsely distributed. Abdomen. Tergites I and III 
reduced to small patches or spots at bases of macrosetae. Coloration. 
Cephalothorax and chelicerae nearly homogeneous light yellow-brown. 
Pedipalps slightly darker. 
Females: Carapace. Thoracic groove a deep pit; circular, irregular, 
or longitudinal. Postocular setae few; form a moderately long, 
roughly single row. Sternum. Fig. 68. Posterior sigilla small and 
far apart. Peripheral setae slender. Longest setae absent from large 
central area. Genitalia. Figs. 147-148. Seminal receptacles very 
weakly sclerotized. Base of stalk relatively thick, elongate, and 
nearly straight. Stalk long, becomes much narrower distally, 3-6 
bends. Bulbs very small. Coloration. Cephalothorax homogeneous 
light yellow-brown. Chelicerae darker light brown to medium brown. 
Variation. There is very little variation among the four males. 
Females: The Grizzly Creek sample (n — 12) has a markedly larger 
mean body size (CL m 4.60 zb .74 mm; range = 3-4 mm-5.8 mm) 
than the Redway sample (n == 14) (CL =fi 3.40 zb .41 mm; range 
— 2.8 mm-4.1 mm). Generally, the larger the specimen the more 
heavily sclerotized and elongate the posterior sigilla; the posterior 
sigilla are round in the smallest specimens and twice as long as wide 
in the largest specimens. There is continuous variation in the degree 
of coiling of seminal receptacles; all specimens fall between, or are 
similar to, the conditions illustrated by Figures 147 and 148. 
Distribution. Humboldt Co. in northwestern California (Map 2). 
