Part 11

$Ceratinella lætabilis.$--This is about the same size as fissiceps,--a sixteenth of an inch long,--but much darker colored, and the males do not have horns or humps on the head. The cephalothorax and sternum are dark brown, and the legs dark orange. The thickened circle on the abdomen (fig. 368) is dark orange brown and the thinner parts gray. In the female the thick circle is usually wanting and the whole abdomen dark gray, with lighter spots around the muscular marks. There are also hardened spots around the stem of the abdomen and under the spinnerets in both sexes. The head is slightly elevated behind the eyes, a little more in the male than in the female. The male palpi (figs. 369, 370) are shorter and stouter than those of fissiceps. It lives in dead leaves and moss, sometimes under stones, and is sometimes found flying in the autumn.

$Ceratinella fissiceps.$--These little spiders are among the smallest species, measuring only a sixteenth of an inch in length. The cephalothorax and abdomen are short and round, and the abdomen has a round thickened spot on the back, more deeply orange colored than the part around it. The head is black around the eyes, and a black line extends backward half the length of the cephalothorax. The head of the male extends forward over the mandibles, carrying with it the front middle eyes, and above it is a rounded hump with the hind middle eyes. The pairs of lateral eyes are opposite the crease between the humps (figs. 371). The female has at the same point a slight crease across the head and an elevation before and behind it. They are very common on low bushes in summer and under leaves in winter, and are occasionally seen in the autumn flights.

$Cornicularia directa.$--The males and females are of the same size and about a twelfth of an inch long. The cephalothorax is brown, varying in different individuals. The abdomen is gray, with the muscular spots lighter than the rest. The cephalothorax is long, narrowing gradually toward the head. In the males there is a slender horn extending forward between the eyes, a little thickened at the end and covered on the upper side with stiff hairs in rows (fig. 376). Under this horn is a smaller one about half as long and close against it (fig. 375). In females the horns are absent, but the shape of the head and arrangement of the eyes are the same, except that the eyes are closer together. There are several other species of Cornicularia, some with similar horns and others with single horns on the heads of the males. They are found under leaves in winter, on plants and fences, and among the flying spiders in autumn.

$Ceratinopsis interpres.$--Length about a tenth of an inch. Color bright orange, with a little black around the eyes and the spinnerets. In the female the height of the head equals the length of the mandibles, and in males it is greater. The size of the sexes is about the same. The upper middle eyes are a little larger and farther apart than the front middle pair, and between them is a flattened space covered with stiff black hairs, longer in the male than in the female (fig. 377). The male palpi have the femur as thick as the femur of the first leg and the tibia very short and wide, with a little recurved point on the front edge. They live on low bushes in summer and under leaves in winter.

THE EPEIRIDÆ

The Epeiridæ are the makers of the familiar round cobwebs. Like the Therididæ and the Linyphiadæ, they live always in their webs or nests back downward or, when in the round web, head downward. The cephalothorax is generally short, as in Therididæ, and low and wide in front, with the eyes near the front edge, the lateral pairs close together and farther from the middle eyes than the latter are from each other. The mandibles are large and strong. The maxillæ are short, often as short as wide, and parallel or a little divergent and rounded at the ends, never pointed or turned inward. The labium is shorter than wide and rounded or slightly pointed at the end. The legs are usually long and, more commonly than in the other cobweb spiders, stout and furnished with spines.

Most of the common species belong to the genus Epeira and its allies, having rounded abdomens and stout legs, some of them with humps and spines and peculiar angular forms of the abdomen. The colors are often bright, and those of the abdomen arranged in a triangular or leaf-shaped pattern. In Meta (p. 190) and Argyroepeira (p. 191) the abdomen is more elongated and the form and marking more like Linyphia. In Tetragnatha (p. 201) the whole body is long and slender, the abdomen several times as long as the cephalothorax, and the maxillæ and mandibles, especially in the males, much elongated. The colors are more uniform and the markings faint, usually light gray, yellow, or green, like the plants among which they live. The round webs of the Epeiridæ consist of a number of radiating lines, varying in different species from a dozen to seventy, crossed by two spirals,--an inner spiral that begins in the center and winds outward, and an outer spiral that begins at the edge of the web and winds inward. The inner spiral is made of smooth thread like the rays, and dust will not stick to it. The outer spiral is made of more elastic and sticky thread, which, when it is fresh, is covered with fine drops of a sticky liquid. In the finished web (figs. 379, 380) the outer spiral covers three-quarters or more of the diameter and the inner spiral a quarter or less, but in the unfinished web (fig. 381), before the sticky thread is put in, the inner spiral covers nearly the whole of it and is cut out, piece by piece, to make room for the outer spiral.

In beginning a web, after the radiating threads are finished, the spider fastens them more firmly at the center and corrects the distances between them by several short, irregular threads (fig. 379) and then begins the inner spiral with the turns, at first close together and then widening, in some species gradually, in others suddenly, until they are as far apart as the spider can reach with the spinnerets on one and the front feet on the next, and so goes on nearly to the outside of the web, where it stops abruptly (fig. 381). The spider usually rests a moment and then begins, sometimes at another part of the web, the outer sticky spiral. In the outermost parts of the web it usually forms several loops (fig. 381, b to f), filling in the corners until it approaches the inner spiral and finds room to pass completely around the web. As soon as the inner spiral is found in the way a part of it is cut out, and by the time the outer spiral is finished the inner is reduced to the small and close portion near the center.

While the temporary spirals are made as far apart as possible, the threads of the outer spiral are placed as close together as they can be without danger of their sticking to each other, and usually a little closer together toward the center of the web than they are at the outside. In fastening this thread to the rays of the web the spider first feels for the last thread with the first and second feet, and, having found it, turns the body slightly around and grasps the ray with the nearest foot of the fourth pair at a short distance from the point where the last thread crosses. After taking hold of the ray with the fourth foot, the spider turns down the abdomen so as to place the spinnerets against the ray and fastens the thread to it, at the same time holding the thread off with the other fourth foot to prevent its sticking to anything around it. The whole making of the web seems to be done entirely by feeling and is done as well in the dark as in daylight.

When the spider is active and the food supply good, a fresh web is made every day, the old one being torn down and thrown away. In tearing down a web (fig. 382) the spider walks out from the center on one of the rays and gathers in what web he can reach with the front feet, chews it into a ball, and drops it; then, having put in new rays in the cleared space, he goes to another part of the web and tears down another piece.

The variations between the webs of different species are chiefly in the central portion. In the webs of hortorum (p. 191), gibberosa (p. 177), and placida (p. 178), which spend most of their time in the web, the close part of the inner spiral is very large, circular, and finely finished, usually showing no trace of the wide temporary spirals. The number of rays is very large, and there is a wide clear space between the inner and outer spirals. In Argiope the inner spiral is very large and widens gradually until it almost touches the outer spiral. It has a closely woven mat in the center and two zigzag bands of white silk extending up and down.

The webs of Tetragnatha, Meta, and Acrosoma have a hole in the middle, the irregular center being entirely removed. Insularis and trifolium live always in tent-shaped nests, with a thread, or several threads, leading to the center of the web. Globosa, labyrinthea, and Zilla have a similar thread from nest to web, and leave open a segment of the web through which it passes.

Insects flying through the web strike the sticky threads and, trying to free themselves, fall against others. The spider at the center of the web feels the movements of the insect and goes toward it by the nearest ray and, drawing out silk from the spinnerets, throws it around the insect until it is tied fast. Adult male Epeiridæ are seldom seen in webs of their own, but some of them do occasionally make webs. The male E. sclopetaria, for instance, sometimes makes a web nearly as large as that of the female and stands in it waiting for insects to be caught.

$The Three House Epeiras: E. sclopetaria, patagiata,$ and $strix.$--These are the round-web spiders most commonly found about houses, barns, and fences. They are all about the same size, a third of an inch in length, and of various shades of brown, with a distinct scalloped middle stripe on the abdomen. Sclopetaria (fig. 383) has the middle stripe broken at the edges just in front of the middle of each side, so as to form two separate figures, one covering the front and the other the hinder half of the abdomen. In patagiata (fig. 384) and strix the edges of the stripe are usually entire for their whole length. In strix (fig. 385) the middle stripe is narrower than in the others and usually lighter in color. The color of sclopetaria inclines to black, with the light marks yellow. Patagiata is oftener reddish brown, especially in alcohol, and the middle stripe is often dark and uniform in color, less broken by spots and transverse marks than in the others. The front legs of sclopetaria are longer than those of the other species, and the front legs of strix shorter and stouter. The cephalothorax of strix is more plainly marked than the others, with three longitudinal stripes. There is not much difference in the markings of the under side. The epigynum has two hard brown prominences at each side, with a soft finger-like appendage between. In sclopetaria and strix this finger is slender and tapers slightly toward the end. In patagiata it is wide at the end and flattened. In the palpi of the males there is a similar difference. Those of sclopetaria and strix are much alike, but that of patagiata has the forked hook at the base much thicker and more curved. Patagiata is a northern species, common in Canada and found occasionally as far south as Massachusetts and New York. It is also common in the north of Europe. Sclopetaria is also a European species, and is seldom found far from houses. It is more common north, but has been found as far south as Norfolk, Va. Strix is common all over the country, both around houses and in bushes.

The webs of these spiders have usually from twelve to twenty rays, and the inner spiral is small and carelessly finished (figs. 379, 380). The webs are made usually at nightfall, very young individuals beginning to spin soon after sunset, and larger ones beginning later, those that are full grown often waiting until dark, but some of them will occasionally spin their webs at any time of day. They stand in the web during the night, but seldom during the daytime, going then to their usual nests or hiding places, sometimes, especially with Epeira strix, a long distance from the web. As a rule, they have no special thread by which to enter or leave the web, but use any one of the rays which may be convenient, always injuring the web more or less; but occasionally, if Epeira sclopetaria has a nest in a convenient situation, he will make the web near it and have a thread direct from the nest to the center of the web, as is the usual habit in some other species. The eggs of sclopetaria are laid in the early summer in large, round, white cocoons (fig. 386), fastened in sheltered places on the walls of houses and covered with a loose mass of silk threads.

$The Angulate Epeiras.$--E. angulata (fig. 389), silvatica (fig. 390), nordmanni (fig. 387), cinerea (fig. 391), and corticaria (fig. 392) all have the humps on the front of the abdomen, and in young spiders this is the widest part. Angulata, silvatica, and cinerea grow to a large size. Cinerea is light colored and lives in great numbers about houses and barns in northern New England. Angulata and silvatica are found among trees and are dark colored like bark. Angulata has a yellow stripe on the sternum and yellow spots under the abdomen between the spinnerets and epigynum. Silvatica has the sternum and under side of the abdomen brown, without any distinct markings. The male angulata has the thickened tibia of the second leg nearly as long as the tibia of the first leg. The male silvatica has the second tibia less thickened and a fourth shorter than the first tibia. The male angulata has a pair of long spines under the coxæ of the second legs, but in silvatica these spines are so small as to be hardly visible. E. nordmanni is a smaller species, about as large as sclopetaria and strix, with light gray colors and generally distinct marking both above and below. E. corticaria is not more than half as large as silvatica and might be mistaken for the young of that species, but the colors are lighter and the rings on the legs narrower and more numerous. The epigynum of corticaria is nearly as large as that of silvatica, and the middle appendage is often wanting as if broken off.

$Epeira nordmanni.$--This is a little smaller and a little longer legged than cinerea and angulata. The abdomen is longer than in those species and has two similar humps in front (fig. 387). The female is not more than half an inch long. The colors are white and gray or black. The cephalothorax is light gray, darkest at the sides, but without stripes. The legs have a dark ring at the ends and a lighter one in the middle of each joint. The abdomen has a distinct middle stripe on the hinder half. In front there is an indistinct dark area extending to the top of the humps and, in the middle, inclosing a bright, long, white spot, with a round spot on each side sometimes united with it. The sternum is dark brown, without any stripe. The under side of the abdomen has a middle dark area in which are four yellow spots, two just behind the respiratory openings and two farther back, halfway to the spinnerets.

$Epeira angulata$ and $silvatica.$--These spiders, which are perhaps varieties of the same species, live usually among large trees and grow to over half an inch in length. The abdomen has two slight humps on the front. The colors are dark, like the bark of trees. The cephalothorax is dark brown, with traces of darker lines in the middle and at its sides. The legs are brown, with darker rings at the ends of the joints and less distinct rings in the middle. The abdomen has a bright yellow spot in front. The middle stripe is darker brown than the rest and has a scalloped edge marked by a dark and light line, which may be entire or broken into lines of spots. The under side of the abdomen is black or brown, with sometimes several yellow spots. The sternum is uniform brown in silvatica and has a yellow middle stripe in angulata. The males are colored like the females and are about half as large, with the legs longer, especially the front pairs. The tibia of the second legs is twice as thick as that of the first pair, a little bent, with the spines stouter and more numerous than in the female. In the male of the angulata variety the tibia of the second pair is nearly as long as that of the first, but in silvatica it is distinctly shorter. On the under side of the coxæ of the second legs is a conical spine, which is longest in the angulata variety. The epigynum is small for so large a spider and has a long slender finger in the middle. These spiders are found singly or in small numbers, usually in the woods, sometimes in webs hung between trees high above the ground.

$Epeira cinerea.$--This large spider is common in the northern part of New England, from Maine to New York, where it lives in great numbers about barns and houses. It grows to three-quarters of an inch in length, with the abdomen proportionally larger than angulata and with two small humps on the front part (fig. 391). The color is dirty white, with grayish markings and long white hairs scattered all over the body. The cephalothorax is a little darkened at the sides, but has no distinct stripes. The legs have gray rings at the ends and middle of each joint, which are hardly visible in some individuals and almost black in others. The markings are like those of angulata, but paler and often indistinct. The sternum is brown, and the under side of the abdomen has a central dark stripe bordered by curved yellow markings. The epigynum is small, as in angulata, but the finger is flattened and turned up at the end. The male is colored like the female, with the hairs on the legs coarser and darker. The tibia of the second legs of the male is not thickened or modified as it is in angulata. The webs resemble those of E. sclopetaria, and the spider has similar habits, standing in the web at night and usually leaving it in the daytime; and it has no special thread from the web to the nest.

$Epeira corticaria.$--This is a small species about quarter of an inch in length, with the abdomen angular in front, where it is as wide as long (fig. 392). The colors are generally lighter and brighter than in angulata or silvatica. The cephalothorax has the cephalic part brown and the sides pale. The legs are marked with broken brown rings at the ends and middle of each joint. The abdomen is brown of various shades, with light markings on the front part that are often bright red or yellow. There is a narrow light line across the abdomen from the middle to each hump and around the outer side of it. In front of these light lines the abdomen is generally darker, except a light spot, sometimes cross shaped, in the middle. The hinder half of the abdomen has sometimes an indistinct middle stripe. The under side of the abdomen has the usual middle dark area, with a curved yellow mark each side of it. The finger of the epigynum is usually absent, as if broken off.

$Epeira trivittata$ and $domiciliorum.$--These spiders, which may be considered varieties of one species, are among the most common Epeiridæ, at least in the northern part of the country, the smaller variety, trivittata, quarter of an inch long, living in small bushes and marsh grass, and the larger variety in trees and fences. The abdomen is only a little longer than wide and is proportionally smaller than in insularis and thaddeus. The legs are long and slender, the first pair being nearly twice as long as the body. The color is most commonly light yellow, with brown markings. Sometimes the abdomen is thickly spotted with red, especially toward the latter part of the summer, and domiciliorum has usually gray and even black markings. The cephalothorax has three dark stripes not very sharply defined, and the legs have brown or gray rings at the ends of the joints. The back of the abdomen has a row of light spots in the middle, sometimes united into a stripe, and on each side of this a row of dark spots nearly surrounded by lighter color. The sternum is bright yellow in the middle, and the under side of the abdomen has a dark center and two or three pairs of yellow spots.

The males are usually smaller than the females, but resemble them in color and markings. On the under side of each femur is a single row of long spines. The tibia of the second legs is curved more in the small than in the large variety and has a row of strong spines on the inner side.

The webs are made usually just before dark, and the spider stands in them more in the night than during the daytime. Sometimes they make a thread from the center of the web to the nest, but this is not a regular habit, as it is with insularis (fig. 397).

Very young spiders make proportionally larger nests, often on the ends of grasses, where their round webs are destroyed every day by the wind. Some of them mature as early as June, and others, especially of the domiciliorum variety, as late as August.

$Epeira pratensis.$--This is the same size and color as Epeira trivittata, and lives, like that species, in grass and low bushes. The cephalothorax and abdomen are both slightly longer than in trivittata, and the color is more uniform. The cephalothorax is dull yellow, with a middle and two lateral stripes, but these are often absent in light specimens. The legs are colored like the cephalothorax, sometimes a little darker at the ends of the joints. The abdomen has a middle dark stripe, at the sides of which are two narrow bright yellow lines, which are sometimes bordered with red. Outside of the middle stripes are six pairs of black spots partly surrounded by yellow. On the under side the sternum has a yellow stripe in the middle, and the abdomen two curved yellow marks, which may be broken into spots. In the male the body is longer and narrower than in the female and longer than the male trivittata, and the tibiæ of the second legs are a little thickened and curved as in trivittata.

$Epeira insularis$ or $marmorea.$--The adult females are half to three-quarters of an inch long, the abdomen large and oval, and bright yellow or orange color, with brown or purple markings (fig. 398). The cephalothorax is dull yellow, with slightly darker lines in the middle and at the sides. The femur and patella of all the legs are bright orange, darker toward the ends. The other joints are white, with brown ends. The light parts of the abdomen are bright yellow marked with brown. In the middle is a narrow deeply scalloped stripe, bordered by a wide yellow line, outside of which are oblique yellow and brown markings. In the middle of the stripe is a row of light spots, each connected at the sides with two others, smaller and round, forming a large figure at the anterior end. On the under side the sternum is brown and bright yellow in the middle. The abdomen is dark brown, with two semi-circular yellow spots. The males (fig. 399) are about half as long as the females. The tibiæ of the second legs are thickened, and the spines on the inner side short and stout. The coxæ of the second legs have a conical spine near the base. This spider lives in bushes three or four feet high. It makes a tent of leaves (fig. 397), in which it usually stands out of sight, holding a thread which leads to the center of the nest. Young spiders make larger tents in proportion to their size and make them entirely of silk (fig. 400). In Massachusetts and Connecticut it matures about the first of September. It is found all over the country, and is probably a variety of the European Epeira marmorea.

$Epeira thaddeus.$--A small species resembling the young of insularis, but with less distinct markings on the back. Full-grown females are about quarter of an inch in length, with the abdomen large and round (fig. 401). The colors are orange and light yellow like insularis. The two front pairs of legs have the femur, patella, and tibia orange, darker toward the ends. The third and fourth legs have the femur and patella orange. The other joints are white, with dark rings at the ends. The tibia of the fourth pair has a wide dark ring at the end. The abdomen is white or light yellow on the upper side, and brown underneath, the edge of the dark color coming far enough up to be seen from above, around the sides and front (fig. 401). Under the middle of the abdomen is a yellow spot just behind the epigynum (fig. 401 a). In some individuals there is a trace of markings on the hinder part of the abdomen, and the under side is sometimes light, so that there is a dark ring around the middle of the abdomen. This spider makes a tent near the web and lives in it like insularis.

$Epeira trifolium.$--This is one of the largest species of the family, measuring from half to three-quarters of an inch long, with a large round abdomen, usually of a purplish brown color, and legs strongly marked with black rings (fig. 403). The cephalothorax is white, with three wide black stripes. The legs are white, with a black ring at the end of each joint and in the middle of the fourth femur. The back of the abdomen varies in color from dark purplish brown to light gray or white, or sometimes light yellow, and the same individual will change from light color to dark. The usual markings are four white spots and a middle row of smaller spots, with several oblique rows still smaller. All trace of the usual middle stripe is wanting except in very young individuals. The under side of the abdomen is dark brown, and the usual semicircular yellow marks are absent except in the young. The males (fig. 404) are not more than half as long as the females and slender and light colored. The markings are like those of the female, but less distinct. The tibiæ of the second legs are not thickened or modified in shape as they are in the male insularis. Trifolium makes a large web in bushes, but seldom stands in it. It has near by a tent above the web (fig. 402) made of leaves, drawn together and lined with silk, connected with the center of the web by a strong thread, and it usually remains in this tent with one foot on the thread, so that it feels when anything is caught. The spiders mature in September, when the males may sometimes be seen about the nests of the females. In October they lay their eggs and all die before winter.