Spiracular area: the anterior of the three areas between lateral and pleural carinae on the metanotum of some Hymenoptera: =first pleural area.
Spiracular line: in caterpillars is that which includes the spiracles: = stigmatal.
Spiracular sulcus: on the metanotum of Hymenoptera, is a grooved linear channel extending from spiracle to apical margin.
Spiral: rolled up like a watch spring, or twisted like a cork-screw. {Scanner's comment: Nowadays it is more correct to regard the corkscrew as helical and the watch spring as spiral.}
Spiral fibre: the spiral thickening or folding of the chitinous lining of a trachea, which gives to the latter its characteristic microscopic appearance as well as its support and elasticity:= ctenidium.
Spirignath: = spiritrompe.
Spiritrompe: the spiral tongue in Lepidoptera.
Splanchnic: applied to the outer embryonic layer of the rudiment of the mid-intestine: or the inner layer of the mesoderm which, becoming applied to the walls of the alimentary canal, develops into the muscle fibres thereof.
Splendens -ent: shining: with a metallic glitter.
Splitter: one who splits or describes species or genera upon minute characters which the "Lumper" (q.v.) deems insufficient to authorize them.