The Thomisidæ are generally flat, short, and widened behind, and have a
sidewise gait and crab-like appearance. The first and second legs are
often much larger than the third and fourth, and all the legs extend
sidewise from the thorax and not forward and backward, as they do in the
Drassidæ (pp. 1-21). The feet have two claws and a thick brush of hairs.
They are generally smooth or covered with very short and fine hair, and
often have coarser hairs scattered at considerable distances from each
other over the back. The eyes are small and in two slightly curved rows,
the upper one longest and often much longer than the front row. The
mandibles are small and narrowed toward the end. The maxillæ are narrow
at the end and slant inward. Most of the species belong to the three
following genera:
Xysticus (p. 30) is flat, with short legs, and marked with gray and
brown, like bark and stones.
Misumena (p. 25) is white or brightly colored. The first and second legs
are much longer than the third and fourth, and there is great difference
between the sexes, the females being large and light colored, while the
males are small, and yellow or green, with red and brown markings.
Philodromus (p. 35) is generally small, with long slender legs, the
second pair longest. The colors are generally light gray and brown,
sometimes with iridescent scales.
Besides the larger genera are several other spiders belonging to this
family. _Tmarus caudatus_ (p. 38) resembles Philodromus in color and
outline, but has besides the caudate abdomen a very different head and
thorax, and the hind legs much shorter than the first and second. _Ebo
latithorax_ (p. 38) is a small Philodromus, with a wide body and
exaggerated second legs. _Thanatus lycosoides_ (p. 40) is like a stout
Philodromus, with rough hairs and markings, resembling some Lycosidæ.
_Tibellus duttonii_ (p. 39) is a long straw-colored spider, resembling
Philodromus in its feet and head, but having a long slender abdomen,
with two black spots.