Ricinuleid reproduction involves indirect sperm transfer using the highly modified distal podomeres of the third legs of the male. This is homologous with the apparatus and technique used by male spiders, which possess elaborate pedipalps. The interpretation of the method of sperm transfer is based upon morphological studies of the male's third legs and the female's genital atrium and the behaviour of males during mating. The male charges the emboli of his modified leg tarsi with sperm from his penis. After climbing on to the back of a receptive female he delicately and precisely places a modified tarsus in the genital atrium of the female. A series of lobes on the tip of part of the modified tarsus fit into a number of vesicular evaginations of the female's genital atrium. The lobes form part of the mechanism which provides a firm attachment of the male's tarsal elements with the female's genital atrium during sperm transfer. A tubular element of the modified tarsus fits into a spermatheca of the female. Sperm and seminal fluid are then injected from the male's embolus into the female's spermatheca.