In these spiders the general appearance is crab-like. The abdomen is not
much larger than the thorax, and both are flat and wide. The first and
second legs are a third longer than the third and fourth. The colors are
usually various shades of brown and gray, in small spots and bands. On
the upper side of each leg is usually a light line, with dark lines on
each side of it. The gait is often sidewise, the legs kept close to the
ground, so that the spider can move in a narrow crack. They live under
stones and bark and leaves, and some, like _triguttatus_, on low plants.
The males have longer legs and smaller abdomen and all the dark markings
larger and darker than the females. In _triguttatus_ there is great
difference between the sexes, but in most species very little, as in
_limbatus_ and _stomachosus_. The head is generally low, and the four
middle eyes form a rectangle a little wider than high (fig. 97).
[Illustration: FIGS. 87, 88. Xysticus stomachosus.--87, female. 88,
male. Both enlarged four times.]
$Xysticus stomachosus.$--A middle-sized and light-colored species, with
gray markings on a light ground, the markings most distinct on the
hinder legs and abdomen. The middle of the thorax is lighter than the
sides, and there is a small dark spot in the middle and a larger one on
each side toward the hinder end (figs. 87, 88). The third and fourth
legs have a distinct dark spot at the ends of femur, patella, and
tibia. The abdomen is light, with a few small spots at the front end and
three pairs of dark transverse bands on the hinder half. The hairs are
short and fine. The male has longer legs and is marked in the same way,
with the spots on the abdomen larger and extended farther forward.
[Illustration: FIGS. 89, 90. Xysticus limbatus.--89, female. 90, male.
Both enlarged four times.]
$Xysticus limbatus.$--This is one of the largest species, the females
reaching a length of a third to half an inch (figs. 89, 90). The thorax
is one-eighth of an inch wide and nearly as long. The abdomen is a
little wider at the hinder end. The legs are short, the longest about
half an inch in length. The whole body is hairy. The color is brown, the
markings dark on a light ground, best shown by the figures. The middle
of the head and thorax is more fully covered by the dark markings than
in other species. There is great variation in the color, and young
spiders are usually lighter than adults. Adult males and females in June
and July.
[Illustration: FIGS. 91, 92. Xysticus gulosus.--91, female. 92, male.
Both enlarged four times.]
$Xysticus gulosus.$--This is a very distinct species and less variable
in markings than _limbatus_ and _stomachosus_. The color is brown or
gray, with indistinct darker markings (figs. 91, 92). The whole body is
covered with fine brown spots and has at the hinder end of the thorax
and on the legs traces of the same markings that show more distinctly in
_stomachosus_. There are a few transverse dark lines on the hinder half
of the abdomen and less distinct longitudinal lines at the sides of the
front half.
The male is a fourth smaller than the female, with a smaller abdomen and
more slender legs, but the same colors and markings. It is usually found
under bark or stones which it closely resembles in color.
[Illustration: FIGS. 93, 94. Xysticus nervosus.--93, female. 94, male.
Both enlarged four times.]
$Xysticus nervosus.$--This is a pale species, the females of which are
nearly as large as _limbatus_. The color is light brownish yellow, with
small spots of lighter and darker color scattered all over the body, and
there are traces of the markings which are more distinct in other
species (figs. 93, 94). On the hinder half of the abdomen are three or
four pairs of very indistinct transverse markings. The legs are marked
with irregular dark and light spots, without any distinct rings or
markings, and the first and second pairs are darker than the others. In
the male the first and second legs are twice as long as the third and
longer and more slender than in the other species. It lives on fences
and under bark.
[Illustration: FIGS. 95, 96, 97. Xysticus triguttatus.--95, female. 96,
male. Both enlarged four times. 97, front of head much enlarged to show
eyes and mandibles].
$Xysticus triguttatus.$--This is a small and very common spider living
on grass and low bushes. The female is about a fifth of an inch long and
the male as large but with a smaller abdomen. The difference in the
color of the sexes is so great that they may easily be mistaken for
different species. The females (fig. 95) are straw-colored, the abdomen
almost white, and the thorax and legs brownish yellow. There are three
black spots at the back of the thorax and indistinct darker bands at the
sides. On the abdomen are two black spots near the front end and three
pairs of broken transverse stripes behind. The male (fig. 96) has the
femora of the two front legs dark brown, the rest like the female or a
little darker. The thorax is dark brown, except in the middle, where it
is a little lighter, as in the female. The abdomen of the male is
strongly marked with transverse black and white stripes, irregular
toward the front end.
[Illustration: FIG. 98. Xysticus quadrilineatus, enlarged four times.]
$Xysticus quadrilineatus.$--Quarter of an inch long, with the thorax a
tenth of an inch wide and the head unusually wide in front. The color is
light yellow, with light brown markings and black spots. The
cephalothorax has four narrow brown stripes, one on each side close to
the edge and the others running back from the lateral eyes (fig. 98);
there are also two fine brown lines sometimes extending from the middle
eyes to the dorsal groove, but usually broken in the middle. There is a
brown spot just behind the dorsal groove and two others in the middle of
the cephalothorax. On the abdomen there are two black spots at the front
end, two in the middle and two near the hind end, besides several
smaller ones along the sides. There are four light brown lines across
the hinder half, each with a white line behind it, and at the sides are
oblique brown lines alternating with white. The legs have a distinct
light line along the dorsal side and are covered with fine brown spots
without any other markings.
[Illustration: FIGS. 99, 100. Xysticus versicolor.--99, female. 100,
male. Both enlarged four times.]
$Xysticus (Coriarachne) versicolor.$--The thorax, abdomen, and legs are
all much flattened, the head is low, and the upper and lower eyes nearer
together than in the other species. The colors are black and gray in
irregular spots on a light ground (figs. 99, 100). On bark or unpainted
wood these spiders can hardly be seen. Light individuals have black
spots on the legs at the end of each joint and the usual three pairs of
dark marks on the abdomen. On the thorax is a white spot in the middle
under the front of the abdomen. Around this spot and behind the eyes is
black extending in spots along the sides. In dark females and in most
males the dark spots are so large that the whole spider is nearly black.
This is a common spider, and a similar species, _Coriarachne depressa_,
is equally common in Europe.