1962] 
Brady — Sosippus 
13 
S. mexicanus as the type species. Sosippus mexicanus has been assumed 
to be the type for the last 64 years. 
Characteristics. Anterior eye row, as seen from in front, procurved. 
Lateral eyes subequal to the median eyes and mounted on distinct 
tubercles. Anterior eye row wider than the middle row; the posterior 
row wider than the anterior row (Fig. 10). Chelicerae robust, with 
prominent bosses. Anterior cheliceral margin with three teeth on each 
side. Posterior cheliceral margin with three or four cheliceral teeth 
on each side, rarely five. Usually constant within a species, but some- 
times variable, e. g. S. mimus. Labium longer than wide, as long as 
wide, or slightly wider than long. Endites, heavily scopulate, slightly 
converging in front of labium, less heavily scopulate. Carapace with 
conspicuous longitudinal thoracic groove. Carapace of females highest 
in the cephalic region, of males usually highest in the thoracic region. 
Sternum always longer than wide. Fourth leg longest. Patella-tibia 
IV longer than metatarsus (except in males of S. calif ornicus, which 
have the metatarsus longer). Order of length of patellae and tibiae: 
IV, I, II, III. Tarsi and metatarsi of legs I and II heavily scopulate. 
Tibia I and II usually scopulate at distal ends. Males with legs longer 
than those of females and more heavily scopulate. 
Female epigynum characterized by a relatively narrow anterior 
median septum connected to an expansive posterior blade (Fig. 19). 
Male palpi with numerous sclerites (Fig. 36). 
The variable nature of certain morphological characters is empha- 
sized because some earlier authors considered such characters to be 
diagnostic for the genus. Some are diagnostic at the species level. 
Discussion. Spiders of the genus Sosippus represent a closely related 
group of species as evidenced by their structural similarity and web- 
spinning habits. It is probable that the group has diverged relatively 
recently in geologic time. Two species groups might be established on 
the basis of structural, similarities and distribution. One group con- 
tains S. jloridanus, S. mimus , and S. texanus. The other group includes 
S. californicus, S. mexicanus , S. agalenoides, S. michoacanus and S. 
plutonus. The illustrations of the color patterns and the drawings of 
the genitalia indicate the affinities within these two species groups. 
C. F. Roewer, first in the Katalog der Araneae (1954) without 
giving reasons, and then in 1959 attempted to separate Sosippus into 
two groups, giving each generic rank. This division is based entirely 
upon the number of teeth on the posterior cheliceral margin. Species 
with four cheliceral teeth on each side were left in Sosippus and those 
with three on each side were placed in the newly erected genus Sosip- 
