The genitalia of the male (left) and the female (right) are engaged as the male attaches a small spermatophore (which contains the sperm and will empty into the female's sperm storage organ) and a larger spermatophylax (which is a nuptial meal that may function to delay the removal of the spermatophore by the female and to provide material that increases egg production or offspring survival). [See Gwynne 2001 for possible functions of the spermatophylax and experiments that test for these functions.]