Читать книгу The Common Spiders of the United States - J. H. Emerton - Страница 7

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These spiders are all pale and most of them without markings. The eyes are close to the front edge of the head and cover more than half its width (figs. 50, 54, 56). The upper row is longer and the eyes larger and the middle pair farthest apart. The distance between this pair varies according to the species. In crassipalpis and canadensis it is little more than that between the middle and lateral eyes, while in rubra it is nearly twice as great. The mandibles of the females are swelled at the base in front, and this swelling is greatest in canadensis (fig. 55). The mandibles of the males are longer and are shaped in a variety of ways according to the species. The shape of the epigynum is indistinct and variable, and females of different species are difficult to distinguish. The females of ornata and excepta are known by their markings and those of rubra by their size and resemblance to the male. The females of crassipalpis and tibialis are doubtful. The palpal organs and male palpi are of great variety and distinguish the males of all species without much difficulty.

Fig. 48. Female Clubiona crassipalpis, enlarged four times.

The Clubionas live in flat tubes of silk on leaves of low plants in summer and under bark and stones at all seasons.

Clubiona crassipalpis.—A quarter of an inch long and pale, without markings. The head is sometimes a little darker than the rest of the body, and the mandibles and ends of the male palpi are always darker. The eyes of the upper row are almost equidistant, the middle pair only a little farther apart than they are from the lateral eyes. The mandibles of the male (figs. 49, 50) are elongated as usual, narrowed toward the end, and thickened in front just above the middle. On the outer side in front is a sharp ridge that extends from the base of the claw halfway up the mandible. The inner edges of the mandibles are thin and inclined backward toward the mouth, but there is no line or ridge between the thick and thin portions as in some other species. The palpi of the male (fig. 51) have the patella and tibia both short. The tibia is widened on the outer side and laps over the tarsus, extending in a blunt hook for half its length.

Figs. 49, 50, 51, 52. Clubiona crassipalpis.—49, head and mandibles of male from the left side. 50, head and mandibles of male from in front. 51, palpus of male. 52, maxillæ, labium, and ends of mandibles.

Figs. 53, 54. Clubiona tibialis.—53, end of palpus of male, showing large tibia. 54, head and mandibles of male.

Clubiona tibialis.—Quarter of an inch long, the same size and color as crassipalpis, with no markings and no dark color except on the mandibles and male palpi. The middle eyes are a little farther apart than in crassipalpis. The male mandibles (fig. 54) are narrower than in crassipalpis and without the sharp ridge on the outer side, but on the inside they are sharply hollowed out with a ridge between the thick outer and thin inner portions. The male palpi (fig. 53) have the patella about as long as wide, as it is in crassipalpis and canadensis, but the tibia is very large, with a hook in the usual place on the outer side and a much larger process, which extends forward over the tarsus. The tarsus is long and thickened in the middle where it rests against the process of the tibia.

Figs. 55, 56, 57. Clubiona canadensis.—55, head of female, showing the swelled mandibles. 56, head and mandibles of male. 57, palpus of male.

Clubiona canadensis.—Quarter of an inch long and without markings. The upper eyes are nearly equidistant, as they are in crassipalpis, but the legs and palpi are shorter. The male mandibles (fig. 56) are much like those of crassipalpis, but have not so sharp a ridge on the outer side. The male palpi (fig. 57) have the patella longer than wide and the tibia wider than long, with two processes on the outer side. The upper tibial process is a simple point extending along the outer side of the tarsus for a quarter of its length. The under process is twice as long, with a projecting corner at its base and running forward to a sharp point, with a round notch halfway between the point and base. The female has the head wider and the mandibles very much swelled in front at the base (fig. 55). The fourth leg is longest and about as long as the body.

Figs. 58, 59. Clubiona rubra.—58, front of head and mandibles of male. 59, palpus of male.

Clubiona rubra.—Smaller than the other species, a sixth to a fifth of an inch long. Cephalothorax light yellow brown, darker toward the front. Abdomen pale in front and darkened with brownish red at the sides and behind and along the middle of the back. The hind middle eyes are nearly twice as far apart as they are from the lateral eyes. The fourth legs are longest in both sexes, and there is little difference in the length of the legs of the two sexes. The mandibles of the female are but little swelled in front, not much more than those of the male, and the male mandibles (fig. 58) are only a little narrowed at the ends. The male palpi (fig. 59) have the tibia very much widened on the outer side, with a short tooth in the middle and two larger short processes on the outer side. The palpal organ has a large dark-colored process in the middle. The epigynum is pointed behind, with a notch in the middle and two black spots under the skin toward the front of the abdomen

Figs. 60, 61, 62. Clubiona ornata.—60, back of female enlarged four times to show markings. 61, palpus of male. 62, front of head and mandibles of male.

Clubiona ornata.—This is one of the few Clubionas that have markings on the abdomen. The general color is pale as usual, but the abdomen has a dark stripe in the middle, broken into spots behind and bordered by pale yellow. At the sides are oblique dark and light transverse markings. These marks are of different sizes in different individuals and connected in different ways. The length is from a third to half an inch. The abdomen is wide across the middle and more pointed behind than in most species. The front middle eyes are about as far apart as in tibialis and nearer than in rubra. The mandibles are not much swelled in front. The legs of the male are longer than those of the female, with the first pair longest, while in the female the fourth pair is longest. The male mandibles (fig. 62) are narrow at the end and hollowed on the inner edges as in tibialis, with a sharp ridge between the thick and the thin portions. The male palpi (fig. 61) have two processes on the outer side of the tibia longer than in rubra and shorter than in canadensis. The tibia is a little widened toward the end and curved outward.

Figs. 63, 64, 65. Clubiona excepta.—63, front of head and mandibles of male. 64, palpus of male. 65, back of female enlarged four times to show markings.

Clubiona excepta.—A third of an inch long and with very distinct gray markings on the abdomen. The cephalothorax is light yellow brown, and the legs are more deeply colored with yellow than in most species. The abdomen is white, with sometimes a yellow mark on the front of the abdomen, and on the hinder half of the abdomen is a middle row of gray spots and a row of larger transverse spots on each side. The fourth legs are longest in both sexes. The male palpi have the tibia longer than usual and patella and tibia about the same length. The tibia has a small process with two teeth (fig. 64). The tarsus is oval and narrow and the palpal organ small.