1870.] REV. O. P. CAMBRIDGE ON THE GENUS IDIOPS. 103 
Labium small, oblong, rather narrower at the apex than at the base. 
Legs strong, variously armed with spines, and terminating with 
three claws, the two superior ones of which are sometimes pectinated. 
Palpi long, strong, and armed with spines ; in the female sex pedi- 
form, and ending with a simple curved claw; in the males termi- 
nating with palpal organs, which in general structure resemble 
closely those of the male sex in all known species of the Mygalides, 
viz. a corneous bulb slightly attached to the underside of the digital 
joint, and prolonged into a variously formed, but generally simple, 
spinous projection. 
M. Guérin remarks that nothing is known of the habits of his 
species I. petitii; the striking similarity, however, in one portion of 
its structure (viz. the strong and peculiar spines on the palpi, legs, and 
falces) seemed to indicate a habit similar to that of Cteniza, Latvr., 
Atypus (Latr.), aud Actinopus (Perty), 7. e. the formation of a tubular 
silken domicile in a hole dug out of the earth, and closed probably 
by a hinged lid: this habit has been verified in respect to one of the 
new species described below (I. syriacus) ; and thus M. Guérin’s 
concluding observation, “ Elle doit étre fouisseuse comme certaines 
Mygales et comme les Atypes,” has received a striking confirmation 
in fact. 
1. Ip1ors FUSCUS. 
Idiops fuscus (Filarie mygaloides), Perty, Del. An. Art. Bras. 
p. 197, pl. 39. f. 5. 
Sphasus idiops, Walck. Ins. Apt. tom. i. p. 379. 
Male adult, length 43 lines. 
Cephalothorax suboval, but slightly convex above. 
Eyes eight, unequal in size; two small ones situate in front, then 
two of larger size, and behind these four small oues, placed in a 
curved line. 
Legs long, rather strong, attenuate towards the tarsi; relative 
length 1, 4, 2, 3. 
Palpi almost as long as the cephalothorax and abdomen, first joint 
forming the maxillz, last joint in the male inflated and unguiculate. 
Abdomen oval; sternum small, flat, subcircular. The whole 
spider is of a dusky black colour ; the coxe of the legs testaceous ; 
tarsired. At first sight similar to “ Actinopus tarsalis,” but in struc- 
ture and position of the eyes wholly dissimilar; on the underside 
the colour is testaceous brown. 
Hab. Brazil. 
In the above description, M. Perty omits a strong specific character, 
well shown in the figure, viz. the strong and tumid radial joints 
of the palpi. 
2. Ipiors Kocut, n.sp. (Plate VIII. fig. 1.) 
Male adult, length 73 lines. 
Cephalothorax large, oval, transversely truncate before, and mode- 
rately convex above ; the lateral and posterior margins of the caput are 
