Motility of Insect Tracheoles

Abstract

THE tracheoles supplying the epidermis in Rhodnius are simple or branched tubes, 200–350 µ in length, tapering gradually from a diameter of 0.7–0.8 µ to end blindly at about 0.2µ. Each is laid down within a single cell, the nucleus of which lies at about one-third of the way along the tube. Once laid down, the tracheoles persist unchanged throughout the life of the insect: they do not shed their cuticular linings at moulting, nor are they converted into tracheæ (cf. Keister¹ on the late stages of Sciara).