after having made some seaming stitches the gripping means 8 will be disenergized by releasing pressurized air from the duct g and supplying pressurized air to the duct h thereby causing the gripper holder movable element 43 of the gripper closing piston 46 to withdraw with a consequent opening of the arms 44 and 45 of the gripper at the end of the seaming operation the operator should recover the small amount of yarn 6 held in the cavity 13 by the crochet 11 by pulling the seamed pieces 3 and 4 without the need of cutting the yarn 6 then the operator will deposit the seamed pieces 3 and 4 and will provide other pieces to be seamed and in the meanwhile the electronic control device will cause the yarn 6 loading cycle to be quickly repeated so as to load again the yarn 6 into the cavity 13 of the crochet 11 thereby eliminating any dead loading delays as well as cutting delays and with a consequent great saving of yarn 6 which in conventional sewing machine is on the contrary randomly taken by the operator for forming the first seaming stitches thus the operator must not take care of the top yarn 6 thereby eliminating any manual operations from the above disclosure and from the observations of the figures of the accompanying drawings it should be apparent that the invention fully achieves the intended aim and objects in particular the fact is to be pointed out that a two yarn sewing machine has been provided which is specifically designed for automatically loading cutting locking and precisely controlling the amount of the top yarn necessary.