Abstract: Disclosed is an apparatus for treating tail yarns in textile spindle assemblies of textile spinning machines, twisters, etc., wherein a stationary upper slit ring and an axially slidable cylindrical member having a lower slit ring at an upper end thereof and a lower portion outwardly expandable by centrifugal force and provided with a spring are mounted on a base portion of a spindle to form a tail yarn gripping means, the pressed state of which is released by sliding the cylindrical member downward by rotational centrifugal force, whereby the yarn underwindings can be automatically removed from the tail yarn gripping means during operation.