Maevia Inclemens

Maevia inclemens is a relatively common and colorful jumping spider of North America. In the males there are two forms, a very rare phenomenon in zoology. These use different courting displays,:3-4 and differ in appearance: the "tufted" morph has a black body and pedipalps ("palps"), three black tufts across its "head", and pale legs; and the "gray" morph has black and white stripes all over its body and legs, orange palps, and no tufts. However, each form accounts for 50% of the adult males, and they are equally successful in mating. A female of Maevia inclemens is 6.5 to 8.0 millimetres (0.26 to 0.31 in) long, while males are 4.75 to 6.50 millimetres (0.187 to 0.256 in) long.:3-4

Like all jumping spiders, M. inclemens has excellent vision. The main eyes, in the front-and-center position, are large, and are more acute than those of a cat and about 10 times as acute as a dragonfly's. The remaining three pairs of eyes are along the sides of the head, and work as motion detectors. The eyes are used for hunting, for avoiding threats and for finding and wooing mates. Almost all jumping spiders are predators, mostly preying on insects, on other spiders, and on other arthropods.

M. inclemens is one of the 11 species in genus Maevia. The species was first called Attus inclemens, and other names have been used. The two male forms look and behave so differently that they were originally considered two distinct species. In 1955 Robert Barnes chose M. inclemens,:1 and this has become the standard name.

The species is found in west southern Canada, and in the United States its distribution forms a crescent from the north mid-west through New England and south to Florida. M. inclemens has been able to establish itself in man-made structures such as outbuildings or fences.