Abstract
The cysticercoid of Tatria octacantha Rees, 1973 from the haemocoele of damsel-fly nymphs consists of an outer and inner cyst. The tegument of the outer surface of the outer cyst bears long slender microvilli which increase the surface area presumably for absorption. The tegument on the inner surface bears electron-dense microvilli and contains vesicles embedded in an electron-dense material. The contents of the vesicles resemble those of the central cavity in which the inner cyst floats freely. Nutrients absorbed by the outer cyst pass into the central cavity where they are available to the inner cyst.