Pirate spiders, members of the family Mimetidae, are araneomorph spiders which typically feed on other spiders.

The family Mimetidae contains roughly 200 species divided among 12 genera, of which Mimetus and Ero are the most common. Mimetids are usually yellow and brown and are usually 3 to 7 millimetres long. Mimetids can be recognized by the rows of spine-like hairs on their long front legs; the rows consist of a long spine, followed by a series of progressively shorter ones.

Mimetidae usually hunt by picking at the strands on their prey's web to simulate the movements of either a trapped insect or a potential mate. When their prey comes to investigate, they are instead captured and eaten. Some mimetids have been observed to feed on insects as well. The spider-feeding habit presents problems in mating, and little is known about how the males court females to avoid being eaten. However, some male mimetids in the genus Gelanor, found in South America, have enormously long appendages which they use to inseminate females.

Source: Wikipedia, the free encyclopedia