Abstract
The larch sawfly, Pristiphora erichsonii (Htg.), like the European spruce sawfly, Diprion (Gilpinia) hercyniae (Htg.), is an obligatoty parthenogenetic ‘species’, that is, it is endowed with the capacity of reproducing without recourse to mating. Wlde this absence of cross-fertilization with the attendant uniformity of progeny it assures renders such species ideally suited for experiments requiring the use of controls, it would at first sight appear ro preclude the adoption of conventional genetic procedures in studying them, other than by circuitous means: it is the main purpose of this contribution to suggest a possible means of circumventing the difficulty.