ULOBORUS. 361 
ULOBORUS. 
Uloborus, Latreille, Gen. Crust. et Ins. i. p. 109 (1806). 
Type U. walekenaerius, Latreille. Europe. 
The species belonging to this genus differ from the types of Miagrammopes and 
Ariston in having the central posterior eyes nearer to each other than to the laterals. 
They live mostly a semi-parasitic life in the webs of large Nephile and other spiders, 
sometimes also in colonies. The commonest tropical form, U. geniculatus, is usually 
abundant in outbuildings, where the beautiful pink angular cocoons can be seen 
hanging in the webs. 
The species which are known to me may be distinguished by the following 
characters. U. diversus, U. albineus, and U. formosus cannot be included in the 
Table, for I am unable to appreciate their differential characters :— 
Males. 
a. Apical lobe of the bulb of the palpus produced into a short, sharp, 
curved spur. Carapace with a dentated pale band running down 
the centre from the posterior eyes. . . signatus, O. P.-Cambr. 
6. Apical lobe of the bulb of the palpus not produced to form a spur. 
Carapace with a basal central and two large oval submarginal 
pale blotches. 2. 1. . we 1 ee ee eee ee ee geniculatus, Oliv. 
Females. 
A. Tibia i. normal, not fringed with hairs in the apical half. 
I. Legs annulate, black, brown, and white. 
a. Carapace brown, with a pale dentated band down the centre. 
a’. See figure of vulva. . . 2. 2. 2 1 ew ew ee ee StYnatus. 
bY. See figure of vulva. . © 1. 1 1 ew ee ew ee «vicinus, O. P.-Cambr. | 
b. Carapace brown, with a pale, basal, central spot and pale 
marginal bands. 
l. See figure of vulva . 2. 2. 2 2 ww wee ee  Cvariegatus, O. P.-Cambr. 
2. See figure ofvulva . . . . Le Loe . . geniculatus. 
Il. Legs pale, unicolorous, or with only the tibia and patella L. 
wholly or partially black. 
a. Tibia i., and often patella also, entirely or partially black. 
Emargination of the posterior margin of the vulva much _ 
broader, semicircular . . . . . 1. sw. ss © Gtnereus, O. P.-Cambr., 
b°. Tibia i. pale, unicolorous. Emargination of vulva much _ 
narrower, /\-shaped . . . . . spernax, O. P.-Cambr. 
B. Tibia i. clothed with a fringe of hairs above and beneath anteriorly. americanus, Walck. 
oY 
BIOL. CENTR.-AMER., Arachn. Aran., Vol. II., May 1902. 3 aL 
