__ ms 
Mr. Blackwall on undescribed Species of Araneid&, 489 
3#,ths of an inch. On the anterior part of the cephalothorax, about the 
region of the eyes, are some longish, black bristles, directed forwards. 
The third and fourth joints of the palpi are short, the latter being the 
stronger, and a long, slender bristle projects in front from the anterior ex- 
tremity of the former: the fifth joint is somewhat oval, being gibbous on 
the outer margin, and having a large process, or apophysis, curved out- 
wards, and notched at its extremity, directed upwards from its superior 
part; it is convex and hairy externally, concave within, comprising the 
palpai organs, which are highly developed, complex in structure, present- 
ing several curved, corneous processes, and are of a red-brown colour. 
The fifth joints of the palpi have their convex sides turned towards each 
other. 
In the autumn of 1834, I found specimens of this spider at Oakland, 
under detached pieces of rock imbedded in a light soil, to the inferior 
surface of which they attach their cocoons, usually two or three in number, 
by asmall, fine web. The cocoon is flat on the side in contact with the rock, 
and convex, with a smail, depressed border, on the opposite one. It measures 
about 4th of an inch in diameter, is composed of white silk of a fine com- 
pact texture, and contains, on an average, between thirty and forty sphe- 
rical eggs of a pale yellow colour, not agglutinated together, but enveloped 
in delicately soft silk. This species fabricates a small, compact, horizontal 
sheet of web in the cavities beneath stones, on the under side of which it 
takes its station in an inverted position. It pairs in the month of Sep- 
tember. An approximation to the Theridia may be traced in the dispo- 
sition and relative size cf the eyes. 
Tribe, LatTericrap&, Latreille. 
Genus, Thomisus, Walckenier. 
Thomisus luctuosus. 
Cephalethorax inversely heart-shaped, convex, depressed in the pos- 
terior region, and broadly truncated before; it is of a brown colour, veined 
with lines of a deeper shade, and hasa fine line of yellowish white on the 
lateral margin; a short band of a yellowish white hue, bifid before, on 
each side of which is a spot of the same colour, situated on an irregular, 
black patch, occupies the medial line of that portion of the cephalothorax 
which is in contact with the abdomen, and a faint brownish white spot oc- 
curs on the inner side of the tubercles on which the anterior eyes of the 
lateral pairs are seated. Eyes disposed in front, in two transverse, curved 
rows, forming 2 crescent ; the lateral eyes of both rows are larger than the 
rest, those of the anterior row being the largest of all, and are situated on 
projections of the cephalothorax. Mandibles short, strong, vertical, cunei- 
form. Maxille inclined towards the lip, which is triangular. Pectus ob- 
long heart-shaped.. These parts, with the legs and palpi, are of a dark 
brown colour, the legs being streaked and spotted with brown of a deeper 
shade, and yellowish white at the joints. The first and second pairs of legs, 
whose dimensions considerably exceed those of the third and fourth pairs, 
are nearly equal in length, the second pair being slightly the longer ; and 
the longitudinal extent of the fourth pair surpasses that of the third. Each 
tarsus has two curved, deeply pectinated claws at its extremity. Abdomen 
oval, depressed, wrinkled, broader at its posterior than its anterior ex- 
tremity, and projects over the base of the cephalothorax ; its colour is 
dark brown obscurely mottled with pale brown and yellowish white, parti- 
cularly on the upper part. Plates of the spiracles reddish brown. 
Length, from the anterior part of the cephalothorax to the extremity of 
the abdomen, 4th of an inch; length of the cephalothorax 4th; breadth 
Third Serics. Vol. 8. No. 49. June 1836. 3D 
