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.
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.
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.
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.
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.
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.
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.
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.
The Tetragnathas are slender, usually straw-colored spiders, living in their webs among the long grass in meadows and near water. The legs are slender, the cephalothorax narrow, and the abdomen long and cylindrical. The mandibles are large in both sexes, and in the males are very long and furnished with long teeth at the end and along the inner margin. When pairing, the male and female hold each other by the ends of the mandibles. The eyes are in two rows nearly equal and parallel, and the distance between the lateral pairs varies in different species. The palpi are long and slender in both sexes, and in the males their proportions differ according to the species. The legs are also long and slender, and vary in length from grallator, where the female has the first legs ten times as long as the cephalothorax, to laboriosa, in which they are seven times as long. The webs are generally inclined and may be nearly horizontal or nearly vertical, according to the place where they are made (fig. 459). The inner spiral is small and has a hole in the middle (fig. 460). The spider stands in the web with the legs extended forward and backward close to each other, except at the ends, where they are turned outward (fig. 459). On account of their similar size and color, the species look at first sight much alike, but there are differences in the arrangement of the lateral eyes and the length of the legs, palpi, and mandibles.
Tetragnatha grallator.—This spider grows to be half an inch long, with the first legs an inch and a half. The mandibles of the female are as long as the cephalothorax, and those of the male longer (figs. 461, 465). In both sexes they are inclined forward, so as to be nearly horizontal and spread apart at the ends. The lateral eyes are near together, so that they almost touch, and the upper row when seen from above is nearly straight. The palpi of both sexes are over one and a half times as long as the cephalothorax, and in the males sometimes twice as long (fig. 465). The patella and tibia together are nearly as long as the femur. The color is sometimes light yellow, but often gray, with a broken middle stripe of darker gray on the abdomen, and three stripes on the cephalothorax. The abdomen is generally enlarged a little in the front third (fig. 461). The males are smaller and more slender than the females, with longer legs and mandibles.
Tetragnatha extensa.—Female a quarter to three-eighths of an inch long, with the first leg three-quarters of an inch. The abdomen is shorter than in grallator, about twice as long as the cephalothorax, and not as much widened in front (fig. 462). The mandibles are two-thirds as long as the cephalothorax and not much inclined forward. The lateral eyes are near together. The colors are often dark, dull yellow brown or gray, with three lines on the cephalothorax and a middle dark stripe on the abdomen, with a light silvery stripe on each side.
The male is smaller and more slender, with the legs longer. The male palpi are one-half longer than the cephalothorax, the femur forming nearly half its length (fig. 466).
Tetragnatha laboriosa.—A little smaller than extensa, with shorter legs and mandibles, the latter short enough in the female to be almost vertical (fig. 463). The abdomen is proportionally longer than in extensa, usually in the females three times as long as the cephalothorax. The first legs are about seven times as long as the cephalothorax. The upper row of eyes is a little curved, so that the lateral pairs of eyes are as far apart as the middle ones (fig. 467). The general color is light yellow. The abdomen is silvery white, with some indistinct gray markings along the middle, and dark stripes on the under side. In the males the mandibles (fig. 467) are short compared with the other species, and are about two-thirds as long as the cephalothorax, and the tibia is very little longer than the patella.
Tetragnatha straminea.—A quarter to three-eighths of an inch long, about the same size as laboriosa, and the same color. The legs, palpi, and mandibles are all a little longer than in laboriosa, and the lateral eyes are farther apart than the middle pairs (fig. 464). In the males the abdomen is shorter and smaller, and the legs longer. The male palpi (fig. 468) are one and a half times the length of the cephalothorax. In females the abdomen is usually three times as long as the cephalothorax and more slender than in laboriosa.
This group comprises several families that differ greatly in form and habits, but agree in having peculiar spinning organs, different from those of all the other spiders. They have the usual six spinnerets and in addition the cribellum (fig. 469), a flat, wide spinning organ, close in front of the other spinnerets and covered with finer spinning tubes. Besides this additional spinning organ they have on the hind legs the calamistrum (fig. 470), a row of hairs that is used to draw out a loose band of silk from the spinnerets. Most of our species belong to the genera Dictyna and Amaurobius and resemble Tegenaria (pp. 96-99) in their feet with three claws, in the arrangement of the eyes, and in their general form and color. The others belong to the small and peculiar genera Filistata, Hyptiotes, and Uloborus.
The Dictynas are all small spiders, not more than a sixth of an inch in length, but are brightly colored and live in webs in open places, where they cannot fail to be seen by any one who looks for spiders. They are not easily frightened, and so their habits can be more easily watched than those of many larger kinds. The heads are high, arching up from the eyes to the highest part opposite the first legs (fig. 476). The eyes are higher and the front of the head is more nearly vertical than in Amaurobius (fig. 489). The head is about half as wide as the thorax and distinctly marked off from it and usually lighter colored. The abdomen is sometimes marked with light yellow on a gray ground, as in Amaurobius, or with a light middle stripe of various shapes, bordered with brown or gray (fig. 487). The whole body is covered with fine hairs, and there are often long white hairs in rows on the cephalothorax. The cribellum is large for the size of the spiders and can generally be plainly seen just in front of the other spinnerets. The calamistrum is not so easy to see, but it covers about half the length of the fourth metatarsus. The peculiarities of the species of these spiders are more strongly marked in the males. The mandibles of both sexes are long and a little curved forward at the ends (fig. 476), but in the males they are sometimes so long that the distance from the ends of the mandibles to the top of the head is as great as the length of the cephalothorax, and the lower ends are turned forward at a sharp angle with the upper part. The mandibles of the males are curved apart in the middle, and they have at the base a short tooth projecting forward (fig. 477). The palpi of the males have a process on the tibia, usually near the base, on the end of which are two spines (fig. 478). There is not much difference in size between the sexes, but they are often very differently colored, and the males do not have the cribellum and calamistrum, or have only rudiments of them.
Some species live on walls and fences, making large webs that become conspicuous from the dust which they collect. Others prefer the tops of plants like stiff grass and the tops of golden-rod and spiræa. Others, like volupis (fig. 474), prefer leaves and the ends of growing branches. The webs are usually irregular, but sometimes are nearly round and formed by threads radiating from the spider's hole, crossed irregularly by other threads (fig. 471).
Dictyna volupis.—This species and frondea are brighter colored and more slender than muraria and volucripes (fig. 484) and live among the leaves of bushes. The female volupis has the legs pale, almost white, and the cephalothorax light brown, darker at the sides and light on the head (fig. 474). The abdomen is yellow in the middle and brown, sometimes red, at the sides. The middle yellow portion forms a regular figure differing much in different individuals. The male is quite differently colored. The cephalothorax, which is larger, is bright orange brown, without much difference between the head and the sides (fig. 475). The legs are light orange, darker than those of the female. The abdomen is dark reddish brown, sometimes over the whole back, but usually with a yellow irregular middle spot smaller than that of the female. The ends of the male palpi are dark colored and as large as the spider's head (fig. 475). The hairs are very fine and light colored and do not modify the color as much as they do in the brown species. The length of volupis is not over an eighth of an inch. The abdomen is oval and not as wide or high as in volucripes and muraria. The head of the male is high, and the mandibles almost as long as the cephalothorax (fig. 476). The lower half is turned sharply forward and flattened out at the end. The mandibles are light orange brown, so that their shape is more readily seen than in the dark species. The tooth on the front of the base of the mandibles is very large in this species (fig. 477).
Dictyna frondea.—This resembles volupis and is likely to be mistaken for it. It is a little smaller, not over a tenth of an inch long, and there is less difference between the sexes. The legs are pale, and the cephalothorax light brown, lighter on the head. The abdomen is gray at the sides, not as red as in volupis, and the middle light stripe is narrower and not as bright yellow (fig. 479). The sternum and under side of the abdomen are gray, as dark as the upper part and sides, while in volupis they are generally lighter. The males have the cephalothorax larger, and that and the legs a little brighter colored than in the female, and the abdomen darker. The mandibles are not as long as in the male volupis, and the ends of the male palpi are much smaller and the tibia longer and straighter than in volupis (fig. 481).
Dictyna cruciata.—About a tenth of an inch long, with the abdomen large and oval, as in muraria. The cephalothorax is light brown above and below, and the legs the same color, but still lighter. The abdomen is gray beneath and at the sides, and silvery white on the back, sometimes over the whole upper surface, but oftener in a stripe widened in the middle so as to form a white cross on a gray ground (fig. 482). The males are darker colored, with the light spot on the abdomen smaller. The male palpi are short and slender, the ends large and rounded and carried close to the head (fig. 483).
Dictyna volucripes and muraria.—These two gray spiders are the common Dictynas on walls and fences and on the ends of grass and weeds, where they make webs shaped according to the places where they live, having in some part of the web a hole in which the spider usually hides (fig. 473). Some allied species make nearly circular webs on walls, with the hole near the center, and gather so much dust as to appear like a spot of dirt (fig. 471). Volucripes is about a sixth of an inch in length, and muraria an eighth of an inch. Volucripes is browner in color and more common on plants, and muraria is grayer and more common on fences. Both species are marked much alike. The cephalothorax is dark brown, partly covered with light gray hairs, some of which form roughly three stripes on the head. The abdomen is large and round, in some females nearly as wide as long. The front half has a middle dark spot of various shapes, and the hinder half two rows of spots connected in pairs with a middle line, forming a figure much like the markings of several species of Epeira (figs. 484, 487). The legs are dark gray or brown, covered with fine hairs, the first pair not much longer than the body. In the females the mandibles are a little thickened in the middle. In the male they are elongated and turned forward at the ends and curved apart in the middle, and have a small tooth on the front near the base. The palpi of the males (figs. 485, 486) are short, with the patella as wide as it is long and wider than the femur and tibia. The tarsus is half longer than wide and pointed at the end. In the tibia there is a little difference between the species that can be seen by looking at the palpi from the side; in volucripes there is a stout process at the base as long as the tibia itself and pointing upward at a right angle with it (fig. 485); in muraria the corresponding process is short and turned forward, and the tibia seems proportionally longer (fig. 486). The cribellum in both these species is large and can easily be seen in front of the other spinnerets. The calamistrum extends over half the length of the fourth metatarsus, which in volucripes is slightly curved.
