In the „Genera des Coléoptères” (VIII, p. 300) Lacordaire, in accordance with Guérin’s views, ascribes to the female of Orion patagonus Guér. a prothorax which is more strongly rugose than in the male and the callosities of which are less numerous and but little conspicuous. Now the Leyden Museum possesses two specimens of O. patagonus (one from Magellan: Patagonia, the other from Cordoba: Argentinia) which, no doubt, are male and female, but these two have the thorax quite similarly sculptured. The male, however, is smaller and of a somewhat brighter colour; it has the antennae somewhat longer, and the apical half of the elytra subshining in consequence of its being rather vaguely sculptured; in the female, however, the apical half of the elytra is opaque coriaceous.