System for connecting a wiper blade to a windshield wiper arm

System for connecting a wiper blade (1) to a windshield wiper arm (2), comprising a coupling device (3) attached to the blade (1) in its central part, and an adaptor device (4, 4a) attachable to said coupling device (3) and capable to be inserted in the grooved end of said wiper arm (2) by means of mutual fitting means, said fitting means including a retainer element (7) projecting through a flexible tab (8), said retainer element (7) being capable to be inserted by fitting it into a housing (9) made in the grooved end of said wiper arm (2). The adaptor device (4, 4a) further comprises a push button (10) associated to said tab (8) of the retainer element (7) and joined to the body of the adaptor device (4, 4a) by means of a weakened section (11) that controls its flexion, said push button (10) being capable to actuate the retainer element (7) to force the disconnection of the adaptor device (4, 4a) with the blade (1) from the wiper arm (2).