joints of its palpi are so tumid as to indicate that it has only to undergo its final change of
integument before it arrives at maturity.
As there does not appear to be the least necessity for adopting the genus Xysticus,
proposed by M. Koch, to which he has transferred this and some other species of British
Thomisi, the generally received method of arrangement has been adhered to in this
instance.
Thomisus cristatus. PI. IV, fig. 38.
Thomisus cristatus, Walck., Hist. Nat. des Insect. Apt., tom. i, p. 521.
— — Latr., Gen. Crust, et Insect., tom. i, p. 111.
i— Sund., Vet. Acad. Handl., 1832, p. 217.
Blackw., Annals and Mag. of Nat. Hist., second series, vol. vii,
p. 448.
— pini, Hahn, Die Arachn., Band i, p. 26, tab. 8, fig. 23.
\ — viaticus, Hahn, Die Arachn., Band i, p. 35, tab. 10, fig. 29.
ulmi, Hahn, Die Arachn., Band i, p. 38, tab. 10, fig. 30.
— lateralis, Hahn, Die Arachn., Band i, p. 40, tab. 10, fig. 31.
Xysticus mordax, Koch, Uebers. des Arachn. Syst., erstes Heft, p. 25.
— viaticus, Koch, Uebers. des Arachn. Syst., erstes Heft, p. 25.
— — Koch, Die Arachn., Band xii, p. 70, tab. 412, figs. 1003, 1004.
'r —-f ulmi, Koch, Uebers. des Arachn. Syst., erstes Heft, p. 25.
Length of the female, |th of an inch; length of the cephalo-thorax, ^th, breadth, n th ;
breadth of the abdomen, ^ths ; length of an anterior leg, &ths; length of a leg of the third
pair, 3th.
The legs are robust, and are furnished with hairs and spines; the first and second pairs,
which are decidedly the longest, and equal in length, have the tibiae and metatarsi supplied
with two longitudinal rows of strong spines on the under side, and the third pair is the
shortest; they are of a dull, reddish-brown colour, streaked with yellowish-white, and spotted
with brownish-black; each tarsus is terminated by two curved, pectinated claws. The palpi
are short, of a dull, reddish-brown colour, with strong spines on the cubital, radial, and digital
joints, and a curved, pectinated claw at their extremity. The cephalo-thorax is large, rounded
on the sides, slightly compressed before, broadly truncated in front, sloped towards the
anterior part, and more abruptly so towards the base; it is provided with a few,
scattered, strong, black hairs, particularly on the anterior part, and is of a dull,
reddish-brown colour, mottled with yellowish-white; the margins, a transverse line
situated between the two rows of eyes, and a large bifid mark in the middle, whose
divarications extend to the posterior eyes, are of the latter colour. The falces are
short, strong, vertical, and have a reddish-brown hue. The maxillm are convex near the
base, and the lip is triangular, but rounded at the apex. These parts, with the sternum,
which is heart-shaped, are of a reddish-brown colour, obscurely mottled with yellowish-brown,
the maxillse and lip being much the darkest. The eyes are disposed on the anterior part of
the cephalo-thorax in the form of a crescent ; the lateral eyes, which are seated on tubercles,
are larger than the intermediate ones, those of the anterior row being the largest of the eight.
The abdomen is depressed, corrugated, particularly on the sides, and has black hairs sparingly
distributed over its surface ; it is broader at the posterior than at the anterior extremity, the
latter, which appears as if cut in a straight line across, projecting over the base of the cephalo-
thorax ; the upper part is of a dark-brown colour, and is marked with five circular
depressions ; the three anterior ones are disposed in a triangle, whose vertex is directed
forwards, and the other two are situated parallel to its base ; a large, strongly dentated,
yellowish-brown band extends along the middle, and the sides and under part have a yellowish-
brown hue, the former being shaded with darker brown ; the branchial opercula are of a
dark-brown colour, bordered with yellow on the inner margin ; and the sexual organs have a
longitudinal, red-brown septum in the middle.
The figures designed on the cephalo-thorax and on the upper part of the abdomen are
nearly alike in both sexes, and the relative length of their legs is the same, but the male is
much smaller and darker coloured than the female. Its abdomen is of a very dark-brown
hue above, inclining to black, and is surrounded by a band of pale, yellowish-white ; the
broad, dentated band extending along the middle is of a yellow-brown colour, mottled with
dark-brown ; the sides and under part are of a dark-brown hue, and the branchial opercula
have a reddish-brown tint. The colour of the tarsi, metatarsi, and the greater part of the
tibiæ of the first and second pairs of legs, is pale, yellowish-brown ; the other parts of those
limbs have a brown-black hue, and the anterior side of the femora of the first pair of legs is
supplied with strong, black spines ; the prevailing hue of the third and fourth pairs of legs is
pale, yellowish-brown, but the tibiæ are marked with dark-brown, and the femora are of a
dark-brown colour, obscurely marked with yellowish-brown. The palpi are short, and of a
brown hue, tinged with red, the cubital, radial, and digital joints being much the palest ; the
radial joint projects two strong apophyses from its extremity, one on the outer side, and the
other, which is larger, more prominent and obtuse, on the under side ; the digital joint is
oval, with a slender, prominent process on the outer side, against th,e base of which the
extremity of the smaller apophysis projected by the radial joint applies ; it is convex and
hairy externally, concave within, comprising the palpal organs ; these organs are highly
developed, complicated in structure, with a strong, black spine curved round their extremity,
and terminating in a point in the slender process on the outer side of the digital joint ; near
their middle there is a black, curved, prominent spine, which has a conical point on its
convexity, and a curved, pointed, projecting process is situated at their superior part, on the
inner side, at the base of which there is a very acute, erect point ; their colour is dark-brown,
faintly tinged with red.
The varieties of Thomisus cristatus, caused by differences in age, condition, and other
circumstances, are very numerous, and many of them have been mistaken for distinct species.
This common spider occurs on the ground and among the herbage of old pastures ; in form
and gait it bears some similitude to a small crab, moving in a lateral direction almost with as
great facility as it does forwards; it is remarkable also for its propensity to take aërial
excursions, particularly when immature. In July the female constructs a lenticular cocoon, of
white silk, of a compact texture, measuring about one third of an inch in diameter, which is