alternating feeds in such a manner that the fabric in zone 16 includes a first course with the yarn 20 feed a2 in fig2 and a second course alternating therewith formed both by the yarn 22 and by an elastic yarn 18 feed a1 in fig2 the yarn 18 is seized by needles raised in a conventional manner up to needle path 19a in the zones where the elastic yarn 18 is not to be seized the needles are raised only to needle path 19b to pick up only yarn 22 after the forming of zone 16 a second edge zone 24 is formed immediately adjacent lip 7 the fabric in zone 24 is modified in the structure to be more elastic with an increased tendency to roll up and with a tendency to resist raveling or breakdown of the stitches toward this end see fig4 and 10 in said portion 24 feed a1 directs the plain or non elastic yarn 22a and the elastic yarn 18a in the same manner as illustrated in fig2 with the path of the needles along the trajectory 19a the exclusion of the elastic yarn 18a during knitting of the remainder of a cylinder rotation is accomplished by lifting the needles only to the lower trajectory or needle path 19b the difference between zone 24 and zone 16 occurs at the second feed a2 fig4 wherein a non elastic yarn 20a is introduced in the alternate course in alternating wales by means of a 1 1 needle selection in such a manner as to constitute the interlacing pattern shown in the lower portion of the fabric in fig5 and 10 this interlacing pattern is formed in a prescribed number of courses.