116 ARANEIDEA. 
certain group of the Selenopide, reserving Selenops for that group of which the Spanish 
species is typical. At present, however, one must leave the matter as it stands. 
The species from Central America described below under the name S. minutus 
presents, in the situation of the eyes, great differences from S. mexicanus, Keys., and 
were it not that intermediate forms occur one would not hesitate to separate these two 
forms under different genera. 
The habits of Selenops are characteristic. ‘These spiders cling to the sides of stones, 
rocks, and logs, darting with marvellous rapidity round to the side which is beneath 
when the stone is turned. It is often impossible even to catch a glimpse of them as 
they dash round and adapt themselves to the chinks and hollows on the surface. The 
coloration and hairy armature tend also to render the spider almost invisible on the 
grey mottled surface of the stones. : 
The genus occurs in the subtropical and tropical regions of all parts of the world. 
The four species known to me may be separated as follows :— 
Males. 
A. Four central eyes in a straight or very slightly recurving row. Lateral 
anteriors equal to one-half the diameter of the adjacent centrals ; about 
equidistant between these and the lateral posteriors. 
i. Spur of tibia of palpus broad, lamelliform, concave on inner side, 
truncate at the apex, not reaching higher than the basal external 
tubercle of the tarsus. 
a. Spur of tibia longer, with a more slender curved basal stem. Apical 
concavity bearing a short stout spur directed from its centre. 
Unca at the external apex of the bulb larger, its point directed 
inward, but not backward. Its base is broadly concave . . nigromaculatus, Keys. 
6. Spur of tibia shorter, without any slender basal stem. Apical 
concavity without a central spur, but with a two-fold lower 
margin. Unca at external apex of bulb, smaller, rising at right 
angles to the plane of the bulb, its point directed downward and 
backward. Its base much narrower and more cylindrical . . . marginalis, sp. n. 
ii. Spur of tibia of palpus very narrow, ensiform, elongate, obtusely 
pointed at the apex, reaching far beyond the external basal tarsal 
tubercle. Unca of bulb very broad at the base, concave, divided 
into two limbs, the outer longer, more slender, directed forward 
and inward, the inner limb shorter, stouter, directed backward and 
downward . 2. 2. 1 ee ee we ee we ew we mevicanus, Keys. 
B. Four central eyes forming a strongly recurved row. Lateral anterior 
eyes equal in diameter to only one-quarter of that of the adjacent 
centrals, situated much closer to the lateral posteriors than to the 
eentrals . 2 2 1. ee ee ee od Uy OE RE a minutus, sp. Ds 
