Oxidase Activity in the Saliva of a Plant-Bug

Abstract

IN an account¹ of the origins of the salivary materials of a lygæid, Oncopeltus fasciatus (Dall.), it was reported that an oxidase other than cytochrome oxidase occurs in the accessory gland of the salivary apparatus, but not in the principal gland. No direct evidence was put forward for the discharge of the oxidase during salivation, but it was stated that the stylet-sheath material shows non-enzymic oxidizing properties that are not apparent in the precursors of the sheath material in the anterior and lateral lobes of the principal gland. It was therefore suggested that an oxidase from the accessory gland acts on the precursors as they are discharged. However, other evidence put forward suggested that the secretion of the accessory gland is a normal constituent of the watery saliva, which can be discharged independently of the sheath material. Evidence for the existence of an oxidase in the watery saliva of another lygæid, Aphanus sordidus Fabr. (the peanut trash bug or groundnut bug), has now been obtained, together with further evidence for the oxidation of the sheath precursors as they are discharged.