1947] 
Spiders from Mona Island 
97 
bium and almost reaches the tip of the palpal organ, 
palpal organ small and confined to the basal two-thirds 
of the joint, embolns a strong black spine with a heavy 
base and does not extend beyond the cavity. 
Female. Length, 5.5 mm., ceph. 2.6 mm. long, 2.0 mm. 
wide, abd. 3.6 mm. long, 2.1 mm. wide. 
C ephalothorax brown, covered with white scales and 
longer dark bristles in the eye area, widest just posterior 
to the dorsal eyes ; eyes same as in the male ; clypeus 
covered with white hairs, less than a diameter of a.m.e. ; 
mandibles pale brown, vertical, promargin of the fang 
groove with three teeth, retromargin with no teeth; ster- 
num and mouth parts same as in the male ; abdomen oval, 
covered with white hairs and longer dark bristles, with 
the pair of broad lateral dark stripes showing nnder the 
white hairs as in the male, on the posterior half the dark 
stripes broken into two pairs of spots, venter pale ; palpi 
pale, covered with white hairs; legs, 4-1-3-2, pale with a 
dark prolateral spot near the tip of the first femur, spines 
the same as in the male ; epigynum shows little exterior 
structure, two lobes with deeply chitinized margins and 
dark spermatheca near the posterior margin. 
Holotype S Mona Island, August 1944 (Beatty). Allo- 
type $ Mona Island, August 1944 (Beatty). Paratypes 
several ?s Mona Island, August 1944 (Beatty). 
Sidusa mona is closely related to Sidusa pavida Bryant, 
from the Virgin Islands. The former has the tibial 
apophysis of the palpus much longer and the embolus 
heavier. Neither belong to the genus Sidusa in the sense 
used by either Peckham or Simon, as there is no tooth on 
the retromargin of the fang groove and there is a dorsal 
basal spine only on the posterior tibiae. But F.O.P.- 
Cambridge has placed in the genus several of the Peck- 
ham genera that eventually may be recognized. 
Literature Cited 
Banks, N. 
1914. New West Indian Spiders. Bull. Amer. Mus. Nat. Hist., 33: 
637-642, pi. 43. 
Bryant, Elizabeth B. 
1940. Cuban Spiders in the Museum of Comparative Zoology. Bull. 
Mus. Comp. Zool., 86: 249-532, pis. 1-22. 
