comprising additional removable thread guiding ducts; FIG. 2 b is a side view of the second embodiment; FIG. 2 c is a plan view of the third embodiment of the present invention comprising guiding means substantially at the distal end portions of the shanks; FIGS. 3 a, 3 b are a side and plan view, respectively, of an apparatus according to the present invention, in a fourth embodiment of a forceps