A hypodermic syringe for the injection of an innoculant liquid including a housing (1), a plunger assembly (2) slidably supported by the housing (1), and a hollow needle (3) which can be fully accommodated within and be extendible from the housing (1). The needle (3) is supported by the plunger assembly (3) and retracts into the housing (1) during an injection stroke of the syringe. The syringe further includes safety means (22, 24) for trapping the needle (3) within the housing (1) after the completion of the injection stroke.
