They are little
feelers beside the faces of both male and female spiders that they use them like little hands, to manipulate food and to clean their faces. With the
Male spider though they are also used to transfer sperm into the vagina, or
epigynum, of the
spider woman. They way they do this is there is like a groove near the females epigynum that the male spider rests his palpi in and then it gets swollen and as it increases in size it just slips right on in the
epigynum and its magic time.
mostly from spiders.arizona.edu