474 
Psyche 
[September-December 
characters. The pedipalpal patella of A. plutonis is distinctively more 
elongate (Figs. 89-90; PPL/PFL and PTL/PPL in Table 1), its 
pedipalpal tibia has a distinctively different shape (Figs. 89-90; 
PTX/PTL in Table 1), and its OCS is drawn out into a broad 
thin lateral keel just below the tip (Figs. 117-118). A. plutonis 
can be distinguished from closely related but allopatric A. erehus by 
the following characters (Table 1) : CL/PCA, CL/PED, CL/IFL, 
and the broad, thin OCS keel (Figs. 117-118). The following ratios 
will separate A. plutonis specimens from those of the other species: 
PSL/PSS, CL/PSL, CL/ITL, and CL/PPL (Table 1). Females: 
A. plutonis females are distinct from those of all other species by 
virtue of their low IVFL/IVML value (Table 2). This is the best 
character to use in separating A. plutonis from its closest relatives, 
A. erehus and A . torridus. The seminal receptacle stalks of A. plu- 
tonis are more elongate and more slender (Figs. 188-191) than those 
of A. torridus or A. erehus. SW/PSS and PSL/PSS (Table 2) are 
useful in separating A. plutonis from most of the other species. 
Description. See Tables 1-3. 
Males: Carapace. Thoracic groove a deep pit, longer than wide; 
anterior border rounded ; narrow posteriorly. Postocular setae usually 
form a double row anteriorly. Sternum. Fig. 63. Posterior sigilla 
large and moderately well separated. Pedipalps. Figs. 89-90, 117- 
1 1 8. Tibia strongly swollen ventrally near distal end; slightly 
swollen more proximally. Embolus base distant from ICS base. 
Conductor tip very sharp. Thin lateral keel-like extension of con- 
ductor (OCS) just proximal to tip so that conductor is markedly 
narrower just proximal of this keel. Inner (concave) edge of OCS 
smooth to slightly rough. Leg I. Fig. 94. Tibia and metatarsus 
with ventral, erect, elongate, attenuate and ensiform macrosetae; 
background setae elongate and not closely appressed. Abdomen. 
Tergites I and III reduced to small patches or spots at bases of 
macrosetae. Coloration. Pars thoracica grey-yellow to light brown. 
Pars cephalica darker, at least along margins and median longitudinal 
line; pale brown to medium brown. Chelicerae match lighter or 
darker portion of pars cephalica. Pedipalps dorsally like pars thora- 
cica. 
Female: Carapace. Thoracic groove a large deep pit; usually 
roughly triangular with front wall straight or procurved. Postocular 
setae distribution variable; single or roughly double longitudinal 
row or long narrow triangular grouping. Sternum. Fig. 76. Pos- 
terior sigilla large and moderately well separated. Stout setae dis- 
tributed around entire periphery of sternum. Most of central setae 
