TETRAGNATHA. 429 
6‘. Apex of basal segment of mandible above with a single 
tooth, or two small teeth only, close to the dorsal spur. 
Apex of cymbium of palpus not bifid. 
1. Conductor of palpus geniculate at the apex. The 
spines on tibie i. and ii., at most, twice as long as the 
diameter of the segment. 
a’, Conductor forming at its apex a concave spoon, with 
a narrow sinuous neck, and aculeate at the point ; 
its base forming two ill-defined spiraloid lobes. 
Apex of basal segment of mandible with two teeth 
near the dorsal spur. . Loe . . « bidens, sp. n. 
b*. Conductor not forming a hollow spoon, but simply 
abruptly curved at its apex; its base forming four 
distinct spiraloid lobes, like the threads of a screw. 
Apex of basal segment of mandible with a single 
tooth only near the dorsal spur . . . . . . . mexicana, Keys. 
2. Conductor of palpus not geniculate at its apex. The 
spines on tibie i. and ii. from three to five times the 
diameter of the segment. 
a’. Tibia of palpus equal in length to the tarsus. Apical 
portion of the tarsus scarcely longer than the basal 
portion, measuring from the base of the tarsus to 
the anterior margin of the bulb. . . . . gracilis, O. P.~Cambr. 
b°. Tibia of palpus one-half the length of the tarsus. 
Apical portion of the tarsus at least twice the length 
of the basal portion, measured as above . . . pallida, O. P.-Cambr. 
++ Tibia of palpus not more than one-fifth the length of the 
tarsus. ww eee eee ee ee eee.) digitata, O. P.-Cambr. 
Females. 
A. Abdomen more or less distinctly gibbous above anteriorly, 
viewed in profile. 
i. Fang of mandible with a more or less well-developed spur on 
the dorsal side towards the base. 
a. Apex of basal segment of mandible beneath bearing a large 
tooth and a smaller adjacent tooth, the latter situated 
between the former and the base of the fang. Upper 
margin of fang-groove with two teeth at the apex and a 
remote series of ten small teeth . . . . . tropica. 
b. Apex of basal segment of mandible beneath ‘without ‘the 
smaller tooth. Upper margin of fang-groove with a single 
long tooth at the apex and a remote series of six smaller 
teeth. 2. ee ee ee ee ee ww we gueatemalensis. 
