REV. O. P. CAMBRIDGE ON NEW BRITISH SPIDERS. - 419 
but in colour and markings there is but little difference; in some males the markings of 
the abdomen are almost obliterated by a general dusky smoky suffusion. 
This species, which is very closely allied to Theridion denticulatum, differs from it con- 
stantly in colour and markings, and is also smaller; it also seems to be entirely a house 
spider. I have found it abundantly for several years in unused rooms, where it spins 
irregular webs in corners and angles, but have never yet met with it out of doors, 
whereas Th. denticulatum is common out of doors in the same locality, and is seldom met 
with in any other locality. 
THERIDION BLACKWALLII, n. sp.. (Pl. 55. no. 16.) 
Male adult, length y% of an inch. 
Cephalothorax short, narrower in front than behind, where it is almost circular; it is 
moderately convex above, prominent at the eyes, and with a strong indentation at the 
junction of the caput and thoracic segment. Colour bright yellow-brown; the margins 
and upper part of caput (occiput especially) and the region of the front row of eyes are 
nearly black. Some strong, bristly, prominent black hairs among the eyes and on the 
clypeus, which is slightly impressed directly below the eyes, and a little prominent 
directly above the insertion of the falces; the clypeus exceeds in height the space between 
the fore and hind central pairs of eyes. 
Eyes eight; four, in two pairs, forming almost a square in the centre, and two on 
each side contiguous to each other, and placed obliquely on a tubercle; those of the hind 
central pair are smaller and rather nearer together than those of the fore central pair, 
which are black, the rest being pearly white. 
Legs rather short and moderately strong. Relative length 1, 4, 2, 3; but the absolute 
difference is not very great between 1 and 4; they are sparingly furnished with hairs, 
and their colour is yellow, banded faintly, but broadly, with orange-brown. 
Palpi moderately long; the bulb formed by the digital joint and palpal organs is of 
great size, exceeding the humeral joint in length; the cubital joint is bent and somewhat 
clavate at its fore extremity, which is furnished with a long, prominent bristle; the radial 
joint is short, but produced on its outer extremity, which is furnished with some bristly 
hairs. The palpal organs, which are directed outwards, are well developed and pro- 
minent, but not very complex; a slender filiform red-brown spine issues from their outer 
extremity, and, curving completely round, rests on their surface, having in contact with it 
a strong fillet of some diaphanous whitish membranous substance ; and at their inner 
extremity is a small black-pointed corneous projection. In colour the palpi are yellow- 
brown, the digital joint being much the darkest. 
Falces rather long, perpendicular, about equal in length to the facial space, slender, 
but a little prominent near their base in front. They are similar in colour to the cephalo- 
thorax, and, as far as could be observed, destitute of teeth on their inner surface. 
Masxille moderately long, strong, of an oblong form, and inclined towards the labium, 
which is short, broad, and semicircular; these parts are a little darker in colour than 
the falces. l 
- Sternum broad, heart-shaped, and of a dark yellow-brown colour. ME 
K 
