1870.] REV. 0. P. CAMBRIDGE ON THE GENUS IDIOPS. 105 
The labium was almost concealed; but it was apparently very 
small, though similar in form to that of Idiops fuscus. 
Sternum somewhat oval in form, but much broader behind than 
before. 
Abdomen small, oval, very convex above, hairy, and of a dull 
yellow-brown colour, rendered blackish above by numerous bristly 
black hairs longer than the rest ; the plates of the spiracles (four in 
number) are of a paler colour than the rest of the abdomen; the 
spinners are also four in number; those of the superior pair being 
much the longest and strongest, and biarticulate. 
An adult male of this Spider was received through Mr. Janson 
from Pebas (Amazons, South America); it seems to be nearly allied 
to Idiops fuscus (Perty), but is much larger, and differs both in the 
relative size and disposition of the eyes, as well as in the structure of 
the palpi. In connecting this species with the name of Dr. Ludwig 
Koch of Niirnberg, I desire to pay a slight tribute of respect to one 
of the keenest and ablest of living arachnologists. 
3. Iprops sigiLLatus, n. sp. (Plate VIII. fig. 2.) 
Male adult, length 9 lines. 
Cephalothoraz broad, nearly circular, and depressed; caput short, 
as if truncated before, and its junction with the thoracic region 
marked by a deep, transverse, and somewhat curved indentation ; 
the other normal furrows and indentations are also pretty strongly 
marked ; the colour of the cephalothorax is ‘a dark yellowish brown, 
and it is sparingly clothed with yellow-grey adpressed hairs, as well 
as some short black spiny bristles; a number of strongish black 
spines and spiny bristles also form a sort of border round its lateral 
margins. 
Eyes eight, placed on a black tubercular eminence of no great 
height, on the fore part of the caput; they are disposed in three 
transverse rows, 2, 2, and 4; those of the foremost row are the 
largest of the eight, near together, and situated immediately above 
the insertion of the falces; those of the second row are much smaller, 
and at some distance behind the former, with which they form an 
oblong rectangular figure, and occupy the summit of the tubercular 
eminence; not far behind these the four remaining eyes form the 
third row, which is much the longest and slightly curved (the curve 
directed backwards); the lateral eyes of this row are large, but 
rather less in size than those of the first row; the two central eyes 
are small (the smallest of the eight), and are further from each 
other than each is from the lateral on its side. From the centre of 
the rectangle formed by the eyes of the first and second rows, one 
or two strong, spiny, black bristles rise almost perpendicularly, 
curving a little backwards; two other bristles of the same kind, but 
shorter, spring up in a transverse line between the central eyes of 
the third row, and have their points directed forwards. 
Legs moderately long, strong; relative length 4, 1, 2,3; they are 
of a reddish yellow-brown colour, and are furnished with hairs, 
bristles, and black spines of varied length and strength: the tibize 
