Muma, 1962: 15-17, figs 9-15; Muma, 1963: 1.
(Muma): Muma, 1970a: 33-34; Muma, 1976: 19; Brookhart and Brookhart,
California: Kern County - Taft, 25 February
1921 (E. O. Essig), 1 male (holotype), 1 female (allotype).
Deposited in the American Museum of Natural History.
Muma, 1962: 15-17,
figs 9-15 (as Therobates arcus):
Total length, 14.0 mm.
Chelicerae 4.7 mm 2.0 mm.
Legs and palpi mangled, not measurable.
Color in alcohol somewhat faded but
apparently light to straw yellow marked with dusky reticulate purple.
Propeltidium dusky except for a median ovate area extending from dark
eye tubercle to posterior margin. Mesopeltidium, metapeltidium,
and abdominal tergites darker yellow than non-sclerotized areas but
apparently not dusky. Palpi dusky on apical ends of femora and all of
tibiae, metatarsi, and tarsi. Legs dusky on distal ends of femora and
proximal ends of tibiae. Leg markings more distinct on fourth legs.
Dentition of chelicerae as shown in figures
10 and 11. Movable finger
with a large, slender, principal tooth and one small intermediate tooth
located at base of principal tooth. Fixed finger long, slender, and
lightly bowed or arched. All fondal teeth distinct from dentate socket
margin of movable finger. Fondal teeth graded in size I, III, II, IV.
Fondal notch J-shaped, somewhat wider than base of fixed finger and
containing one denticule.
Groove of fixed finger a shallow,
parallel-sided slot that is mesoventral but not extending to base of
finger. Flagellum complex typical of group, with dorsal tubular bristles
not strongly arched and apical plumose bristles slightly S-shaped but
not flattened or otherwise modified. Mesial setae of movable finger
plumose on proximal half of finger but simple distally.
Eye tubercle situated on anterior margin of
propeltidium. Eyes separated by slightly more than one diameter.
Propeltidium wider than long by a ratio of 1 to 1.5.
Metatarsus and tibia of palpus with
scattered, long, slender spines; long, heavy cylinder bristles below and
small fine ones above. Metatarsus with a scopula of 50 to 60 widely
spaced papillae extending entire length of segment (fig. 12). Metatarsus
of palpus about 3.5 times as long as tarsus.
First post-spiracular abdominal sternite
provided with four long flattened ctenidia extending well beyond
posterior margin of succeeding segment (fig. 13).
Total length, 18.0 mm.
Chelicerae 5.8 mm
4th legs 17.0
Color in alcohol similar to that of male.
Dentition of chelicerae as shown in figures 14 and 15. Movable finger with
principal tooth moderately large, three intermediate teeth of which anterior
is tiny and denticulate, an anterior tooth slightly smaller than principal
tooth, uneven serration in front of anterior tooth, and low ridge in place
of mesial tooth. Fixed finger with principal and medial teeth equally large,
smaller anterior tooth, two intermediate teeth between principal and medial
teeth, two between medial and anterior teeth, and indistinct serration in
front of anterior tooth. Fondal teeth
same as in male.
Structure similar to that of male
except there is no scopula on the metatarsus of palpus and no distinct
ctenidia on first post-spiracular abdominal sternite.
Opercula of genital segment as shown in figure 9.