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]).