a way that the yarn will face the opening of channel 62 fig9 when it is displaced by the air jet the device of fig4 to 11 is also provided with yarn guides 67 67 39 or other yarn guide organs which perform the same function as the guide yarns 21 21 39 of fig1 to 3 the operation of the device hereinbefore described and the process which it carries out are as has been said different as to conception from those of the prior art indeed the nozzle and more precisely the portion thereof which constitutes the air orifice and the zone adjacent thereto has the additional function of deviating the yarn from its theoretical rectilinear trajectory and of imparting thereto a tension having the resultant in the desired direction as a result were no air to be fed to the nozzle the yarn would slide on the nozzle orifice the air jet displaces the yarn from the orifice and the resultant of the tension urges the yarn constantly back against the orifice therefore the nozzle proper concurrently performs besides its normal air feed function additional functions which in the prior art devices were performed by different portions of the interlacing device the nozzle proper according to the invention besides causing the displacement of the yarn from its rest trajectory by the impact of the air jet also has as has been said the function of initially containing such displacement a further containment being effected by the control and guide organ which in its.