 Its eyes are able to gather available light more efficiently than the eyes of cats and owls, and are able to do this despite the lack of a reflective layer (tapetum lucidum); instead, each night, a large area of light-sensitive membrane is manufactured within the eyes, and since arachnid eyes do not have irises, it is rapidly destroyed again at dawn.Two genera formerly included in this family, "Avella" O. P-Cambridge, 1877 and "Avellopsis" Purcell, 1904, are now placed in "Menneus"., the World Spider Catalog accepts the following genera