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.
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.
Spongioplasm: the net-like structure of protoplasm in a cell.
Spongiose: a soft, elastic tissue resembling a sponge.
Spur: a short, stiff, generally blunt process and usually not articulated at its base: in the plural refers to paired spiniform processes at or near the end of tibia:.
Spur formula: a numerical expression of their arrangement; as 2-3-4; two spurs on fore tibia, 3 on middle, and 4 on posterior; in Trichoptera.
Spurius: false: applied to aborted anterior legs in some diurnal Lepidoptera.
Spurious cell: in Diptera (Pack.), = 3d anal (Comst.).
Spurious veins: certain folds or thickenings in the wing surface which resemble a vein so nearly as to be readily mistaken and sufficiently constant to be useful in classification.
Squama: in Odonata, the sclerite that bears the palpus of both maxilla and labium: the scale-like first abdominal segment of some ants: a scale-like appendage covering the base of primaries in Lepidoptera, and so = patagium; q.v.: a small scale above the halteres in Diptera: in this order Packard uses squama for the lobed scale and restricts alula to the lobe-like appendage: Osten-Sacken uses squama for the posterior scale alone and antisquama for the anterior.
Squames: the flattened, fimbriated or spine-like marginal processes of the pygidium in Diaspinae, other than the lobes and true spines: = "plates," of Comst.; or "scaly hairs" of Maskell.