Terminal line: in Lepidoptera, runs along the outer margin of the wings.
Terminal space: the area between the s. t. line and terminal line in certain Lepidoptera.
Terminology: the technical nomenclature of any science.
Termitarium: a nest, natural or artificial, or a colony of Termites.
Terrestrial: living on or in the land; opposed to aquatic.
Tessellated: checkered; more or less like a chess-board. {Scanner's comment: More correctly, it means "tiled", covered with possibly regularly shaped areas or pieces. They may or may not be square or otherwise regular.}
Test: the secretionary covering of Coccidae, and especially such as are waxy, horny or glassy.
Testaceous: dull yellow brown; tile colored [pale cadmium yellow+burnt sienna].
Testes: the tubular structures in the male, in which the production of spermatogonia, and often also of later stages in the development of the sperm takes place.
Testicular follicles: in the larva, are those structures which in the adult form the tubes composing the testes; in the adult applied also to the tubes forming the testes.