Part 5

THE GENUS PHILODROMUS

In these spiders there is less difference in length between the front and hind legs than in Misumena or Xysticus. The legs are long and slender, the second pair longest, and the body is small and flat, and the abdomen pointed behind. The colors are brown and gray, and the whole body is often covered with fine flattened hairs that in the males are iridescent. Philodromus vulgaris lives usually on houses and fences, but the other species on plants.

$Philodromus vulgaris.$--About quarter of an inch long, the legs of the female spreading over an inch and those of the male an inch and a quarter (figs. 101, 102). They often stand with all the legs extended sidewise, flat against a wall or fence which they closely resemble in color. When freshly molted they are covered with fine gray hairs of the color of weathered boards, that obscure most of the markings. Older spiders or those wet with alcohol are covered with small gray spots forming a stripe in the middle of the front of the abdomen and a herringbone pattern on the hinder half. The edges of the back of the abdomen are dark and form a sharp line against the light color of the under surface. The thorax is darker in the middle and at the sides in irregular spots of gray. The legs are spotted and darker toward the ends of the joints. The under side of body and legs is light colored.

$Philodromus ornatus.$--This is a small species about one-eighth of an inch long. The female is very distinctly marked with dark brown on a white ground (fig. 105). The middle of the thorax is white and the sides brown nearly to the edge. The abdomen is white, with a distinct brown band on each side from the front more than half its length backward. Sometimes there is also an indistinct brownish pattern in the middle, but this is usually absent in adults, and the middle is entirely white. Under the abdomen the lateral brown bands extend backward and meet around the spinnerets. The abdomen is wider than in most species,--nearly as wide as it is long across the hinder half. The male is very differently colored. The legs and thorax are orange brown, darker at the sides of the thorax and toward the ends of the legs. The abdomen is darker brown and strongly iridescent with red and green in a bright light. In alcohol it shows indistinctly the same markings as the female. The legs are longer and the abdomen narrower, as in males of other species.

$Philodromus lineatus.$--The female of this species is a little larger than ornatus, the brown markings are lighter, and, in life or when freshly killed, purplish in the lighter parts. The markings are less distinct than in ornatus, the brown and white running into each other. The abdomen has a brown band each side, often broken into several spots, and a brown band in the middle extending back half its length, behind which are several lighter marks (figs. 106, 107). Between these are several oblique lighter markings and rows of spots. The legs are light gray, darker toward the ends of the joints.

$Philodromus pictus.$--Female about one-fifth of an inch long, the abdomen nearly twice as long as the thorax, with the widest part across the middle farther forward than in most species (fig. 110). Legs and palpi pale yellow with fine brown spots. Thorax light yellow in the middle and reddish brown at the sides, covered with fine spots. Abdomen dull red at the sides and bright yellow in the middle, with a dark mark in the middle of the front half and two dark marks behind it on the hinder half. The eyes are surrounded by distinct light rings. In some specimens, usually immature, the abdomen has a more distinct yellow and red pattern (fig. 108). The male (fig. 109) has the thorax and legs darker and the abdomen less bright red and yellow than the female, sometimes gray and iridescent.

$Ebo latithorax.$--In color and general appearance this resembles Philodromus, but is at once distinguished by the length Of the second legs, which are more than twice as long as any of the others (fig. 111). The thorax is wider than long, and the abdomen is wider than in Philodromus. The head is narrow and rounded in front. The front middle eyes are largest and farthest forward. The colors are gray and white, with black spots in the darker parts, as in Philodromus. The length is not much over an eighth of an inch and the length of the longest legs quarter of an inch.

$Tmarus caudatus.$--This spider is about as large as Philodromus vulgaris and similarly colored, but may be distinguished from it by the height of its abdomen and the short tail or projection over the spinnerets (fig. 113). The thorax is round at the sides and square in front, and the mandibles are inclined forward so that they can be seen from above. The two rows of eyes are farther apart than in Philodromus, and the lateral eyes of both rows are raised on tubercles. Among the eyes are several black spots that may be mistaken for extra eyes, and there are similar spots on the legs, most thickly on the front pairs. On the back of the thorax are radiating white lines. The abdomen is light in front and marked behind with two or three pairs of indistinct transverse lines (fig. 112). On the under side the whole body and legs are pale, without spots except a wide middle band of gray under the abdomen. The third and fourth legs are shorter than the first and second, the difference being greater than in Philodromus and less than in Misumena.

$Tibellus duttonii.$--This is a very common spider on bushes and grass. The body is slender, from a third to half an inch long, and a tenth of an inch wide (fig. 115). The thorax is an eighth of an inch long, widest across the hinder half and narrowed toward the front, where it is cut off nearly straight over the mandibles. Both rows of eyes are strongly curved (fig. 116). The hinder row is twice as long as the front row and all the eyes larger. The abdomen is straight at the sides and a little pointed behind. The color is light gray or yellow, with a darker gray line in the middle, divided into two toward the eyes. At the sides of the thorax are other longitudinal lines. On the abdomen, one-third its length from the hinder end, is a pair of small round or oval black spots. The legs are light gray, with no markings except a few black hairs.

$Thanatus coloradensis$ or $lycosoides.$--In color and general appearance this resembles Philodromus, but is not as flat, and the legs are not as long and slender. The general color is light gray, with a distinct wide light stripe in the middle of the thorax, and a dark brown pointed stripe with white edges in the middle of the front half of the abdomen (fig. 117). The head is a little longer and higher than in most Thomisidæ, and the abdomen is a little longer and not so much widened behind. The eyes are much as in Philodromus, but larger and nearer together. The whole body is hairy, with longer and darker hairs scattered among the short ones. The males differ but little from the females except in having a little longer hairs and darker color. They live on plants and may be mistaken for Philodromus (p. 35) or for Ocyale undata (p. 88).

THE ATTIDÆ

The Attidæ are jumping spiders, many of them brightly colored and quick in their movements and living in open places among the tops of low plants. They are usually short and stout spiders, with a large cephalothorax, which is wide in front, where the eyes have a peculiar arrangement in three rows (fig. 118), somewhat as in the Lycosidæ, but with the middle eyes of the front row much the largest, so that at first sight many of them appear to have only two eyes. The eyes of the second row are very small and hard to see, and those of the third row are far back on the head and usually turned a little backward. The front legs are usually thicker than the others, especially in the males. The relative length of the legs is variable, the first pair being commonly the longest, but sometimes the fourth and even in some species the third pair. The feet have two claws, with many fine teeth and a thick brush of hairs. The Attidæ are usually thickly covered with hair or scales, often brightly colored or iridescent, and their appearance is often entirely changed by rubbing or wetting.

They walk backward or sidewise as well as forward, and many of them jump great distances. They make no cobwebs, but some species make silk tubes or bags on plants or under stones in which they hide to molt or lay their eggs or to pass the winter. There are often great differences in color and markings between the sexes, and the males have peculiar bunches of hairs and color spots on the legs and head. At the mating time some of the males have peculiar ways of approaching the female, holding their legs extended sidewise or over their heads in such ways as to display their ornaments. These mating habits have been well described by G. W. Peckham, who has made a special study of this family, in the Occasional Papers of the Wisconsin Natural History Society, of Milwaukee, in 1889. This family is largely represented in more southern countries, and our species belong to a great number of genera most of whose members live farther south.

$Attus palustris.$--Large females are quarter of an inch long, the males a little smaller. The cephalothorax is a quarter longer than wide, shorter in proportion to its width than in the next species, Saitis pulex, which it much resembles. The two sexes resemble each other in markings, but the females are lighter and browner and the males darker and grayer. The cephalothorax has a narrow white middle line, widened opposite the dorsal eyes, and a shorter white line just below the eyes on the sides (fig. 119). The edge of the cephalothorax is also white. On the abdomen the front middle spot is not so distinct as in pulex, but in place of it are two white spots. Behind these is a large transverse light marking, sometimes broken into two spots. The legs are dark or light gray, without any distinct markings. The male palpi are smaller than in pulex, though the males are larger. Palustris lives on plants and makes nests among the leaves.

$Saitis pulex.$--This is one of the smallest of the family. It is about a sixth of an inch long, sometimes even smaller. The colors are various shades of gray like the ground, and when still it is hard to find, but it is an active spider and exposes itself by jumping in open places. The cephalothorax is half longer than wide, longer and narrower than in Habrocestum and Attus. The abdomen is usually shorter than the cephalothorax and wider (figs. 120, 121). The cephalothorax has a large light-colored triangle in the middle, covering the head between the eyes in front and ending in a point behind. In alcohol this spot disappears, especially in the males, and the head appears black between the eyes and light behind and at the sides. The front half of the abdomen has a light middle stripe, lightest at the edges and darker gray in the middle. Behind this is a transverse white spot nearly the whole width of the abdomen and behind it several smaller light markings. In the male these markings are brighter and the surrounding dark color blacker than in the females. The legs are marked with indefinite spots of dark gray on a lighter ground, the contrast stronger in the males. The hairs all over the body are short and fine and the spines on the legs distinct, especially in the males.

$Habrocestum auratum.$--In life this spider is covered with bluish white hairs that give it a light gray color and obscure the markings. The markings of the male are so much stronger that those of both sexes can be best understood by describing the male first (fig. 122). The cephalothorax has a white middle stripe for a short distance back from the front eyes and two distinct white stripes from the lateral front eyes back the whole length. In the middle of the head are two small white spots and just behind them between the posterior eyes two curved white lines. The latter marks show indistinctly in the females. Down at the sides of the cephalothorax are white stripes meeting in front under the eyes. The abdomen has a white line extending entirely around it and a middle stripe of varying width.

The female (fig. 123) has only faint indications of the markings of the cephalothorax, usually a little lighter color in the middle and at the sides below the eyes. The white stripe around the abdomen is broken into three pairs of oblique white markings and the middle stripe into several spots or pairs of spots. There is nothing distinctive in the markings of the under side or of the legs except the ornaments of the male.

The front legs of the male (fig. 125) in this species are much ornamented. The femur has long black hairs on the under side. The patella has long black hairs beneath, a spot of short black hairs on the inner side, and a crest of long white hairs mixed with shorter black on the upper side. The tibia is covered with long black hairs except at the tip, where they are white. There is nothing peculiar about the third leg (fig. 124). The form and general appearance can best be understood from the figures.

At the mating time the males, as they approach the females, hold the front legs extended sidewise and lifted a little from the ground, with the tibia nearly horizontal and the tarsus turned downward. In this position they advance slowly, at the same time running rapidly sidewise from one side to the other and at short intervals jerking the abdomen and the front legs slightly upward. They go almost close enough to touch the female and then quickly retreat.

$Habrocestum peregrinum.$--This is about the same size as auratum and looks very much like it. The female, at any rate in alcohol, has a more distinct light mark in the middle of the cephalothorax, curving under the eyes and pointing forward in the middle (fig. 128). The abdomen has light markings in the middle similar to those of auratum, but those at the sides are less distinct.

The male has the white stripes in the middle and around the abdomen like auratum. The cephalothorax has the same white lines at the sides under the eyes and at the posterior end. It does not have a middle white stripe on the head between the eyes or two white spots just behind it, as auratum has, but the marking behind the eyes is more distinct, as it is in the female. The front legs of the male (fig. 127) are not ornamented with long hairs like auratum, but the third legs have a very peculiar shape, the patella being wide and flat, with a dark spot in the middle of the front side (fig. 126). The shape of this joint is best shown by the figure. When approaching the female he holds up the front legs and draws in the third pair so that the ornamented patellæ show from in front.

$Habrocestum splendens.$--A little larger than the other species, with the female distinctly marked with black and white and the male with brilliant red and iridescent scales. The females are about a quarter of an inch long, sometimes longer, and the males are a little smaller. The cephalothorax of the female is covered with brown scales mixed with black hairs. Across the middle, just behind the dorsal eyes, is a light band that curves behind the eyes and extends forward in the middle. The abdomen has a white band in front, one on each side, and one in the middle, the rest being deep black. The shape of these markings varies and the black parts are often broken into two rows of spots. The cephalothorax of the male is covered with dark iridescent scales, with blue, green, and purple reflections. The abdomen is covered with bright red shiny scales mixed with fine black hairs. It is lighter in front and at the sides, and in the middle shows indistinctly through the scales dark markings like those of the female (fig. 129). The legs are dark like the cephalothorax.

Mr. Peckham says that when the male approaches the female he lifts his abdomen into an almost vertical position so that the red color shows from in front. Then he rises on the tips of his feet and, with the front legs off the ground and pointing forward, he dances back and forth sidewise in front of her, gradually drawing nearer. At intervals he stops and turns his back to her, then faces her and dances again.

$Neon nellii.$--This is one of the smallest spiders of the family, only a tenth of an inch in length. The general color is dark gray, darkest toward the head. The cephalothorax is high, the highest part being a little behind the middle, from which it curves downward to the front eyes and slopes abruptly backward (fig. 130). The eyes are large and prominent, the front row nearly straight and as wide as the widest part of the cephalothorax. The posterior eyes are nearly as large as the front middle pair and are in the middle of the cephalothorax. The abdomen is a little longer and wider than the cephalothorax (fig. 131). The cephalothorax is smoky gray, darker toward the front and darker in males than females. The abdomen is gray, with yellowish markings in a herringbone pattern through the middle. Common under stones and leaves at all seasons.

$Zygoballus bettini.$--This is a very beautifully colored spider, having in life spots of white hairs and shining scales of the color of copper and bronze. The cephalothorax of both sexes is high and wide in the middle and slopes down steeply from the posterior eyes under the front of the abdomen (fig. 132). The top of the cephalothorax between the eyes is nearly square. The posterior eyes are almost the full width of the cephalothorax apart, and the front row of eyes is nearly as long. The cephalothorax is dark brown covered with iridescent scales. The legs are pale, except the dark femora of the first pair and dark spots on the ends of the joints of the fourth pair. In the male all the legs are a little darker than in the female and without the spots on the fourth leg. The abdomen of the female is light brown, marked with white in a row of irregular spots. In the male the abdomen is brown, covered with shining scales and with a white band around the front and two white spots on each side. The mandibles of the male are much elongated and bent apart at the ends to make room for the long claw. At the inner angle is a large tooth, and there is another one of complicated shape on the middle of the under side.

$Phidippus multiformis.$--This is a very common spider on plants throughout the summer. It matures in July, and the males and females are so little alike as to be taken for different species. The males (fig. 134) are black, with white and orange markings on the abdomen, while the females are brown mixed with black, white, and yellow scales and small white spots.

The usual length is about a third of an inch in both sexes. The cephalothorax is nearly as broad as long, and the abdomen of the female as wide as the thorax and a little longer.

The general color of the adult female is yellowish brown, with black and white markings (fig. 133). Around the front of the abdomen is a white band, and on the back are two indistinct longitudinal black stripes in which are four pairs of white spots. The general brown color is produced by a mixture of scales and hairs of various colors. The females are most brightly colored just before reaching maturity, and then there is a large proportion of yellow and orange scales in their covering and the black stripes and white spots are more distinct. The hairs and scales are of various shapes, the most common being that of slightly flattened hairs. The yellow and orange scales are wider and less pointed, and the white spots have short and wide scales. Under the abdomen the color is light gray, with two parallel darker stripes. The legs are pale in the middle of the joints and dark toward the ends and covered with gray and black hairs. The palpi are light yellow.