The Common Spiders of the United States

by J. H. Emerton

THE GENUS LINYPHIA

These spiders vary in size like the species of Theridium, from a quarter of an inch to a tenth of an inch long. In appearance they differ greatly from Theridium; the cephalothorax is longer and higher in front, the legs are long and slender, with distinct spines, and the abdomen is sometimes a little flattened on the back as in Steatoda, but oftener high in front and a little pointed toward the spinnerets. The sexes differ little in size, but often in color and markings. The palpal organs and the terminal joints of the palpi of the males are very large and complicated, and in the smaller species form the best means of distinguishing them. There are a great number of minute species of Microneta, Bathyphantes, and other allied genera, but only the larger and more common are here described.

Linyphia marginata.—This is one of the most common web spiders in shady woods all through the summer. It is a sixth of an inch long, with slender legs, the longest of which are usually half an inch. The cephalothorax is two-thirds as wide as long, the middle of it brown and the edges light. The abdomen is flat on top and widest and thickest behind, the colors light yellow and purplish brown [(fig. 319)]. In the middle there is a dark stripe, consisting usually of three parts united by a narrow line, and behind this is another dark spot. At the sides are several dark stripes, the front ones lengthwise and the hinder vertical, all connected with the dark color of the under side. The legs are light yellow without markings, and the hairs and spines fine and not easily seen. In the males all the colors are darker and the abdomen narrower, with only a few light marks at the sides. This spider has no nest, but lives all the time in the middle of its web. It matures in June, and the young brood are common in their small webs in August and September.

The web of L. marginata [(fig. 318)] is in the form of a dome four or five inches in diameter, hung between rocks and plants, seldom much concealed by leaves. The threads are fine, and the web so transparent that it easily escapes notice unless the sun shines upon it. The meshes are larger than in L. phrygiana and other flat web-making species. The depth and width of the dome depend somewhat on the shape of the opening in which it is made, and the number and length of the supporting threads vary according to the surroundings. The spider stands apparently all the time under the top of the dome. Insects flying near touch the threads above the dome and, their flight being broken, drop down among closer threads and, finally, to the dome itself, where they are caught by the spider and taken through the meshes. Remains of insects and other rubbish are cut loose from the web and dropped. The webs seem to be used for a long time, but if they are injured a new one is soon made, either in the night or day, and the remains of several old webs are often seen hanging flat and torn below a new one. The dome is begun at the top and extended downward by inclined threads, an inch or two long, which are crossed by shorter threads in all directions [(fig. 321)]. The spider works very rapidly, but I have never seen a dome finished, the spider always working a few minutes and then resting a long time.

Linyphia communis.—A little smaller than marginata, with legs a little shorter. The colors are the same light yellow and purplish brown, but the markings are distinctly different. The cephalothorax is uniform light brownish yellow. The middle stripe of the abdomen extends the whole length of the upper side and connects with several narrow brown stripes that extend down the sides [(fig. 323)]. The abdomen is more regularly oval and less enlarged behind than in marginata, but the upper part extends back farther over the spinnerets. The under side is dark brown. The male is smaller than the female, with the head higher and the abdomen narrower. The palpi of the male are unusually small for the genus [(fig. 324)]. The web of communis [(fig. 322)] consists of a horizontal sheet, convex below and supported by threads above. Below this, about an inch distant, is another sheet of web. Insects flying between the upper threads fall down to the sheet below and are taken through by the spider, as they are in the dome of marginata.

Linyphia mandibulata.—A little larger than L. communis and marginata, with the head longer and more distinct from the thorax, and the abdomen larger and flattened on the top (figs. [326, 327]). The length is about a sixth of an inch. The cephalothorax is dark orange brown, and the legs a lighter shade of the same color. The length of the legs is about as in communis, shorter than marginata and phrygiana. The abdomen is dark brown, often almost black, with several white spots, usually two across the front end and several others around the sides [(fig. 326)], sometimes forming a complete light stripe around the middle. In the males the abdomen is narrow, and the only markings are usually the two spots on the front end. The cephalothorax of the male is long and narrow; the head is extended forward, and the mandibles inclined backward toward the maxillæ. The mandibles are more than half as long as the cephalothorax and widened at the ends, with four teeth on the inner corner [(fig. 329)]. On the inner side of the mandibles, near the middle, is a large blunt tooth.

The webs are flat and near the ground, on short grass and leaves and across little hollows in the sod [(fig. 325)]. The webs are not as large as those of phrygiana, and the spider has no nest, but stands always in the web and drops suddenly when alarmed. It lives all over the eastern part of the country and resembles closely the Linyphia pusilla of Europe.

Linyphia coccinea.—About a sixth of an inch long and bright red and orange color. The size and length of legs are about the same as in communis. The legs are light orange, the cephalothorax a deeper shade of the same color, and the abdomen light red. The palpi have the ends black, and the legs are sometimes streaked with black. The hinder middle eyes are twice as large as the others and twice as far apart as the front middle pair. The space between and around the middle eyes is black. The top of the abdomen is a little flattened and extended back in a blunt black point over the spinnerets [(fig. 330)]. The male [(fig. 331)] differs little from the female except in the more slender abdomen and longer legs. The male palpi are as long as those of the female and only a little thickened at the ends. The blackened point on the end of the abdomen is less distinct in the male than the female. The web is a little concave, not as deep as that of marginata and with smaller meshes. It is made among low plants. This is a common species in the South.

Linyphia phrygiana.—This is one of the most common species and lives both in the woods and around houses. It is larger than marginata and communis, measuring a fifth of an inch in length. The cephalothorax is light yellow, with a black line in the middle, forked at the front end, and another at the sides near the edge of the thorax. The legs are light yellow, with a dark ring at the end of each joint and at the middle of each tibia and metatarsus. The legs are also marked with dark spots, especially on the femora, and the spines are black and conspicuous. The abdomen is yellowish, with brown spots at the sides and beneath, and along the middle of the back is a dark brown or red herringbone stripe [(fig. 333)]. The head of the male is higher than that of the female and has a crest of stiff hairs. The male palpi [(fig. 334)] have a long spur on the patella and have the end small, like communis. The web [(fig. 332)] is a large flat sheet, sometimes over a foot across. A corner of it usually runs under a stone or other hiding place, and here the spider stands, often making a little tent in connection with the web.

Linyphia (Stemonyphantes) trilineata.—About a quarter of an inch long, with a large oval abdomen and comparatively short legs. The color is light yellowish gray, the cephalothorax with three dark lines, and the abdomen with three rows of dark spots partly connected in lines. The legs are marked with dark rings on the ends and middle of the joints, more distinctly on the under than on the upper side. The sternum is light in the middle and black around the edge, and the abdomen has irregular black spots at the sides and beneath. The male has longer legs and wider thorax and smaller abdomen. It lives under stones and logs and winters under leaves in the woods. It is common both in this country and Europe.

Linyphia (Bathyphantes) nebulosa.—Length a sixth of an inch. Color light brownish yellow, with gray markings [(fig. 338)]. Some are almost white, and others are dark, with the black spots covering a large part of the body. The cephalothorax is dark on the edges and has a dark middle stripe, forked toward the eyes. The abdomen has six or seven pairs of irregular dark spots, more or less connected with a dark middle line. The under side of abdomen and sternum have black spots which, in dark individuals, run together, making these parts entirely black. The legs have dark rings on the ends and middle of the femora and tibiæ. The spines are long and darker than the skin. The epigynum is folded twice, so that only part of it is seen extending out from the under side of the abdomen (figs. [340, 341]). The palpus of the male [(fig. 339)] has large and complicated appendages at the end. In general shape it is rounder than in the next species, and the angle at the base of the tarsus is less prominent. This spider is common in cellars and other damp and shady places about houses. It is common in Europe and is perhaps imported. The web is flat, like that of L. phrygiana, and often large for the size of the spider, sometimes covering a pail or box a foot wide.

Linyphia (Bathyphantes) minuta.—One-eighth of an inch long, a little smaller than nebulosa. The cephalothorax is yellowish brown, darker at the edges, but without any middle line. The dark markings of the abdomen nearly cover it, so that it appears dark gray with light markings instead of light with dark markings, as in nebulosa. The legs are light brownish yellow, with dark rings on the ends and middle of the femora and tibiæ. The epigynum is folded twice, as in nebulosa [(fig. 343)]. The male palpi [(fig. 344)] have a general resemblance to those of nebulosa, but there are some distinct differences. The tarsal hook is very large and has a longer and narrower point than nebulosa. The tarsus has on the outer side near the base a conical point roughened with short ridges. This is more prominent in this species than in nebulosa. It lives in cellars and similar places often in company with nebulosa.

Linyphia (Drapetisca) socialis.—This very distinct species is marked with gray and white and is often found on the bark of trees without any web. It is a tenth to an eighth of an inch in length. The cephalothorax is white with black edges, a black spot in front under the eyes, and a black mark in the middle, from which indistinct lines radiate toward the edge. The abdomen is widest just behind the middle [(fig. 345)]. It is white, mottled with gray, and has a black stripe on each side and several pairs of black spots in the middle, connected with a middle line. The legs are white, with a gray ring at the end and middle of each joint. The spines are long on the legs and palpi [(fig. 347)]. The mandibles have an oblique dark stripe and several long hairs in front and a row of teeth in front of the claw. The epigynum [(fig. 346)] is large and extends obliquely backward away from the abdomen and curves inward again at the end. It lives all over the northern part of this country and Europe, under leaves and sometimes on trees, where it is occasionally found on the bark without any web.

Linyphia (Helophora) insignis.—An eighth of an inch long, as long as socialis, but more slender. The cephalothorax and legs are light yellow, and the abdomen gray or white, sometimes without markings and sometimes with gray stripes at the sides and two or three pairs of gray marks across the hinder half [(fig. 348)]. The cephalothorax of the male is twice as wide across the middle as at the head. The legs are without markings. The epigynum [(fig. 350)] is long and straight, extending backward close to the abdomen for half its length. The tibia of the palpal organ has a short, pointed process, extending directly outward from the side [(fig. 348)]. They live in flat webs among low plants.

Linyphia (Diplostyla) concolor.—About a twelfth of an inch long, a little smaller than nigrina, with long slender legs, and the abdomen slightly pointed toward the spinnerets and not much larger than the cephalothorax. The color is light yellow brown, the abdomen gray without any markings. The epigynum (figs. [352, 353]) has a long, slender, flexible process on the outer edge that extends backward to the middle of the abdomen, and under it is another shorter one not easily seen. The tarsus of the male palpus [(fig. 351)] is longer and more tapering than that of nigrina. Adults of both sexes are common under leaves in winter all over the northern part of the country.

Linyphia (Diplostyla) nigrina.—A tenth of an inch long. Cephalothorax and legs light yellow brown. Abdomen dark gray or black, with five or six transverse light markings, usually in the male and often in the female broken into pairs of spots [(fig. 355)]. The abdomen is high in front and a little pointed behind [(fig. 354)]. The epigynum (figs. [356, 357]) has two flexible processes, one over the other, extending backward, the tip of the inner one extending beyond the outer. The tarsus of the male palpus [(fig. 356)] is short and truncated, with its tube twisted in a circle around the end. It lives under leaves in winter.