Most spider wasps are black, metallic blue, or reddish and measure from 1 to 5 cm (0.4 to 2.0 in) long. The wings range from clear to smoky-gray or bright red-orange in color. Their extraordinarily long hind legs distinguish spider wasps from other wasps. Spider wasps are usually seen walking on barren ground or in tangled undergrowth searching for prey. As they walk, their wings flicker and their antennae tap the ground. They often break their restless walking with short flights.