THE GENUS TETRAGNATHA

The Tetragnathas are slender, usually straw-colored spiders, living in their webs among the long grass in meadows and near water. The legs are slender, the cephalothorax narrow, and the abdomen long and cylindrical. The mandibles are large in both sexes, and in the males are very long and furnished with long teeth at the end and along the inner margin. When pairing, the male and female hold each other by the ends of the mandibles. The eyes are in two rows nearly equal and parallel, and the distance between the lateral pairs varies in different species. The palpi are long and slender in both sexes, and in the males their proportions differ according to the species. The legs are also long and slender, and vary in length from grallator, where the female has the first legs ten times as long as the cephalothorax, to laboriosa, in which they are seven times as long. The webs are generally inclined and may be nearly horizontal or nearly vertical, according to the place where they are made [(fig. 459)]. The inner spiral is small and has a hole in the middle [(fig. 460)]. The spider stands in the web with the legs extended forward and backward close to each other, except at the ends, where they are turned outward [(fig. 459)]. On account of their similar size and color, the species look at first sight much alike, but there are differences in the arrangement of the lateral eyes and the length of the legs, palpi, and mandibles.

Tetragnatha grallator.—This spider grows to be half an inch long, with the first legs an inch and a half. The mandibles of the female are as long as the cephalothorax, and those of the male longer (figs. [461], [465]). In both sexes they are inclined forward, so as to be nearly horizontal and spread apart at the ends. The lateral eyes are near together, so that they almost touch, and the upper row when seen from above is nearly straight. The palpi of both sexes are over one and a half times as long as the cephalothorax, and in the males sometimes twice as long [(fig. 465)]. The patella and tibia together are nearly as long as the femur. The color is sometimes light yellow, but often gray, with a broken middle stripe of darker gray on the abdomen, and three stripes on the cephalothorax. The abdomen is generally enlarged a little in the front third [(fig. 461)]. The males are smaller and more slender than the females, with longer legs and mandibles.

Tetragnatha extensa.—Female a quarter to three-eighths of an inch long, with the first leg three-quarters of an inch. The abdomen is shorter than in grallator, about twice as long as the cephalothorax, and not as much widened in front [(fig. 462)]. The mandibles are two-thirds as long as the cephalothorax and not much inclined forward. The lateral eyes are near together. The colors are often dark, dull yellow brown or gray, with three lines on the cephalothorax and a middle dark stripe on the abdomen, with a light silvery stripe on each side.

The male is smaller and more slender, with the legs longer. The male palpi are one-half longer than the cephalothorax, the femur forming nearly half its length [(fig. 466)].

Tetragnatha laboriosa.—A little smaller than extensa, with shorter legs and mandibles, the latter short enough in the female to be almost vertical [(fig. 463)]. The abdomen is proportionally longer than in extensa, usually in the females three times as long as the cephalothorax. The first legs are about seven times as long as the cephalothorax. The upper row of eyes is a little curved, so that the lateral pairs of eyes are as far apart as the middle ones [(fig. 467)]. The general color is light yellow. The abdomen is silvery white, with some indistinct gray markings along the middle, and dark stripes on the under side. In the males the mandibles [(fig. 467)] are short compared with the other species, and are about two-thirds as long as the cephalothorax, and the tibia is very little longer than the patella.

Tetragnatha straminea.—A quarter to three-eighths of an inch long, about the same size as laboriosa, and the same color. The legs, palpi, and mandibles are all a little longer than in laboriosa, and the lateral eyes are farther apart than the middle pairs [(fig. 464)]. In the males the abdomen is shorter and smaller, and the legs longer. The male palpi [(fig. 468)] are one and a half times the length of the cephalothorax. In females the abdomen is usually three times as long as the cephalothorax and more slender than in laboriosa.