[Illustration: FIG. 437. Web of Acrosoma spinea.]
These are small spiders, with the abdomen extended back half its length
beyond the spinnerets, brightly colored, flattened above, and furnished
with several pairs of pointed processes. The cephalothorax is longer
than in Epeira and Argiope and widest in the middle. The legs are
slender and have only fine and soft hairs. The webs (fig. 437) are
inclined and have a hole in the middle surrounded by several turns of
smooth thread; when hanging in it the spiders look like burrs or seeds.
At a slight alarm they will sometimes drop to the ground and hide under
the nearest shelter.
[Illustration: FIG. 438. Acrosoma mitrata, enlarged four times.]
$Acrosoma mitrata.$--This is a smaller species than _rugosa_ or
_spinea_. The abdomen does not extend as far backward as in the other
species, but comes farther forward so as to cover half the cephalothorax
(fig. 438). The abdomen is truncated behind, with two pairs of pointed
processes at the corners, one pair below the other. In front, the
abdomen is a little narrowed over the thorax. The legs and cephalothorax
are brown, as in the other species. The abdomen is light yellow, darker
behind, with two or three pairs of black spots along the middle and five
or six dark elongated spots along the sides. The under side is black
mixed with yellow spots, as in the other species. Common as far north as
Connecticut.
[Illustration: FIG. 439. Acrosoma rugosa, enlarged four times.]
$Acrosoma rugosa.$--This has five pairs of spines on the abdomen, three
pairs in the same places as those of _spinea_ and the other two pairs
behind and under the last of the three. All the humps and spines are
about the same size. The cephalothorax and legs resemble those of
_spinea_, but the legs are shorter. The colors are white, yellow, and
brown in spots and marks like those of _spinea_, some individuals being
almost white, and others as nearly black. The males have a long slender
abdomen without humps or spines. This is a common spider as far north as
Connecticut, where it is occasionally found.
[Illustration: FIGS. 440, 441, 442. Acrosoma spinea.--440, female
enlarged four times. 441, male enlarged four times. 442, young less than
half grown.]
$Acrosoma spinea.$--This spider is distinguished from all the common
species by the shape of its abdomen, which is narrow in front and has
two long spreading points behind (fig. 440). There is a pair of smaller
spines on the front of the abdomen and another near the middle of each
side. The middle of the abdomen is white or bright yellow. The spines
are black at the points and bright red at the base. There are several
black spots on the back, and gray marks at the sides. The under side of
the abdomen is darker than it is above and marked with black and yellow
spots. The cephalothorax and legs are light brown, the thorax with
lighter edges. The young have the abdomen longer, with the posterior
spines short and blunt. The third and fourth legs are whitish, with dark
longitudinal stripes. The males are smaller than the females and
resemble the young. The abdomen is a little widened behind and has in
place of the spines three pairs of low bumps. The front legs are dark,
and the hinder legs light, as in the young. The web (fig. 437) has a
hole in the middle, across which the spider hangs.
[Illustration: FIGS. 443, 444, 445. Meta menardi, enlarged four
times.--443, 444, half-grown young. 445, back of adult female.]
$Meta menardi.$--This spider lives in caves and similar cool and shady
places in various parts of this country and also in Europe. In general
appearance, especially when young, it reminds one of Linyphia. The
abdomen is longer than wide, high in front, and tapering a little behind
(fig. 445). The eyes are near together, the lateral eyes almost as near
the middle pairs as they are to each other. The mandibles are long,
thickened in front near the base, and slightly turned outward at the
ends and strongly toothed on the inner side about the claw. The maxillæ
are also long and a little widened at the ends. The dorsal groove is
very deep. The legs are long, the front pair twice the length of the
body. The full-grown female is half an inch in length, the male a third
shorter, but with legs nearly as long. The general color is gray, the
lighter parts translucent and yellowish. The cephalothorax has three
gray stripes, more distinct in the young, a middle stripe from the eyes
to the dorsal groove, and one on each side of the thorax. In the young
(fig. 444) the markings of the abdomen are two large dark spots near the
front end and several other pairs, becoming smaller toward the hinder
end. In adults these markings unite into a middle stripe more like
Epeira, with a light middle spot in front and several middle spots and
pairs of spots diminishing backward. The legs have gray rings at the
ends and middle of the joints. The webs are horizontal or inclined,
according to the shape of the rocks on which they are built. They
resemble the webs of Tetragnatha, having a small central spiral with a
round hole in the middle, across which the spider holds herself. This
spider matures late in the autumn or early in the summer, and makes
large, loose, and transparent cocoons, hung near the webs.
[Illustration: FIGS. 446, 447. Argyroepeira hortorum, enlarged four
times.--446, under side of female. 447, back of female.]
[Illustration: FIG. 448. Argiope riparia in the middle of the web.
Natural size.]
$Argyroepeira hortorum.$--This is a green and silver-white spider,
with slender legs and a long abdomen resembling Tetragnatha. The body of
the female is about a quarter of an inch long, the abdomen twice as long
as wide, and blunt at both ends (fig. 447). The first pair of legs are
twice as long as the body, the second a fourth shorter (fig. 446). The
legs are bright green, darker toward the ends. The cephalothorax is
green, with a darker stripe in the middle and one on each side. The
upper part of the abdomen is silver white, with a dark line through the
middle, giving off four pairs of branches at the sides. At the sides of
the abdomen are yellow stripes extending downward, and toward the hinder
end two bright copper-red spots. The colors of the under side are as
bright as those above and are more plainly seen as the spider hangs in
its web. The basal joints of the legs are light in color, and the
sternum and mouth parts dark. The abdomen is green, darker from front to
back, where it is almost black around the spinnerets. In the middle is a
large double spot of bright copper red, and the red spots at the end of
the body show as plainly from below as from above, and around the middle
spot are several small spots of bright yellow. The hairs and spines of
the legs are so fine that they do not much affect the general color. On
the front side of the femur of the fourth leg there is a fringe of long
hairs extending half its length. The males are half as large as the
females, with longer and more slender legs and palpi, and the same
colors. The webs are nearly horizontal, with a small hole in the center,
and under the round web is often a large irregular web. The round web
may be a foot in diameter, or it may be so small as hardly to cover the
spider. The webs have a large number of rays, and the spirals are very
close together, as in the webs of _Epeira gibberosa_ (fig. 413). The
smooth central part of the web is circular and very regularly woven,
showing usually no trace of the beginning of the temporary spirals, and
between it and the sticky circles there is a wide space in which is
nothing but the bare rays.
[Illustration: FIGS. 449, 450. Argiope riparia.--449, female. 450, male
enlarged twice.]
[Illustration: FIG. 451. Middle of web of Argiope riparia, natural size.
The large inner spiral ends at _b_ and the outer spiral at _a_. At _c_,
_c_, are thickened spots on the rays where the inner spiral was attached
while the web was making.]
[Illustration: FIG. 452. Rudimentary web of male Argiope riparia of the
natural size. Part of the web of the female at the left shows the
difference between the webs of the two sexes.]
$Argiope riparia.$--This and the next species are among the largest and
most conspicuous of the round-web spiders. It lives among grass and low
bushes in open fields and meadows, especially along the borders of ponds
and ditches. It matures in the northern states about the first of
August. Large females are nearly an inch long, with the front legs
longer than the body (fig. 449). The cephalothorax is nearly as wide as
long and covered with silvery white hairs, except around the eyes. The
front legs are entirely black, and the others are black, except the
femora, which are light red or yellow. The abdomen is oval, a little
pointed behind and square in front, with two small humps at the corners.
There is a black stripe in the middle of the abdomen, narrowed between
the humps and widened in the middle, where it includes two pairs of
yellow spots. Along the sides are two bright yellow bands or rows of
irregular spots. The color underneath is black, with a yellow stripe on
the sternum and two wide yellow stripes on the abdomen, with small
yellow spots between and at the sides. The young differ considerably
from the adults. Until nearly full grown the legs are distinctly marked
with dark rings on the ends and middle of each joint. When very young
the abdomen is slender, the color is pale, and the markings gray,
without the strong black and yellow of the adult. The male (fig. 450) is
only a fourth as long as the female, similarly colored, but with the
markings less distinct and the palpi very large. In the middle of the
summer they live near the webs of the females, where they make small and
imperfect webs of their own (fig. 452). The females make webs, sometimes
two feet in diameter, with a zigzag band (fig. 448) of white silk up
and down across the middle, and a round thick spot where the spider
stands. The inner spiral of these webs is very large, covering a quarter
of their diameter (fig. 452). The outer spiral comes very near it, but
the spider sometimes passes through the narrow space between them from
one side of the web to the other. The web is usually a little inclined,
and on one or both sides sometimes has a screen of irregular threads two
or three inches distant from it (fig. 453), but these are often absent.
These spiders have no nest and stand all the time in the center of the
web (fig. 448). Sometimes the spider draws away the grass and leaves so
as to make an oval opening large enough for the web (fig. 453). In
September the eggs are laid in large pear-shaped cocoons with a brown
paper-like surface, hung by threads among the grass and bushes (fig.
454). The young hatch during the winter and remain in the cocoon until
May. The adult spiders disappear in October and probably all die before
winter.
[Illustration: FIG. 453. Web of Argiope riparia in an oval opening among
plants from which the leaves have been drawn away by the spider. At the
left of the web is a screen of irregular threads.]
[Illustration: FIG. 454. Egg cocoon of Argiope riparia in marsh grass.
Natural size.]
$Argiope transversa.$--This species is a little smaller than _riparia_.
It lives in the same places and matures a little later, about September
1. The abdomen is more pointed than that of _riparia_ (fig. 455). The
ground color is white or light yellow, and is crossed by a great number
of black transverse lines, which are sometimes obscured, especially in
young spiders, by a thick covering of silvery-white hairs. The
cephalothorax is covered with white hairs through which the dark
markings on the sides show indistinctly. The legs are light yellow, with
black bands at the ends and middle of each joint. The femora of the
first legs are sometimes entirely black. The young have the back
entirely white. The markings of the under side are similar to those of
_riparia_. The male (fig. 456) is colored like the female, but is only a
fourth as large. The legs are yellow, marked with black spots, but have
no rings. It has the same habits as _riparia_. It remains in its web
later in the season, and makes a cocoon flattened on the top (fig. 458)
instead of narrowed to a neck, like those of _riparia_.
[Illustration: FIGS. 455, 456. Argiope transversa.--455, female. 456,
male. Both enlarged twice.]
[Illustration: FIG. 457. Web of Argiope transversa in an opening among
marsh grass, covered above by wilted ends of grass leaves.]
[Illustration: FIG. 458. Egg cocoon of Argiope transversa in marsh
grass.]
This species often makes its web in marsh grass, which it draws away and
fastens with silk (fig. 457). As the surrounding grass becomes long and
weak, it sometimes falls away, leaving the web in a basket of grass
fastened firmly enough together to remain standing.