Spatula: the breast bone (q.v.) of cecidomyid larvae. Spatulate: rounded and broad at top, attenuate at base. Specialization: the adaptation of an organ to a definite purpose, or of an organism to fit a determinate environment. Species: an aggregation of individuals alike in appearance and structure, mating freely and producing young that themselves mate freely and bear fertile offspring resembling each other and their parents: a species includes all its varieties and races. Specific character: a feature common to all individuals of a species, by means of which they may be distinguished from all other individuals of other species: = essential character. Specular: mirror-like: transparent. Specular membrane: in male Cicada, the inner or posterior mirror-like membrane of the sound-organ: = mirror. Speculum: a transparent area or spot on wings of some Lepidoptera; the glassy areas at base of tegmina in male Orthoptera that serve as sounding boards: a spot on the neck of some caterpillars. Sperm: the seminal fluid: in plural form is sometimes used as = spermatozoa; q.v. Spermatheca: = spermatotheca; q.v. Spermatid: the final cells which are converted without further division into spermatozoa: they arise by division of the second spermatocytes (Wilson). Spermatocytes: the cells arising from the spermatogonia. The primary spermatocyte arises by growth of one of the last generation of spermatogonia. By its division are formed two secondary spermatocytes, each of which give rise to two spermatids (Wilson). Spermatogenesis: the development of spermatozoa. Spermatogonia: the descendants of the primordial germ cells in the male. Each ultimate spermatogonium typically gives rise to four spermatozoa. Spermatophora: a sac or case containing spermatozoa. Spermatotheca: the sac or reservoir in the female, that receives the sperm during coition: = spermatheca and receptaculum seminis. Spermatozooen-zoa: the male cell or cells which, by uniting with the ova, fertilize them. Spherical: in the form of a sphere: a body in which all diameters are equal. Spherule: a minute sphere or globule. Spicula: a slender needle-like process: e.g. the sting in bees: also employed as = ovipositor: q.v. Spiculiform: like a slender, needle-like process. Spiculum: a small spicule or thin, pointed process. Spinate: produced into an acuminate spine. Spindle-shaped: cylindrical, elongate, thicker in the middle, tapering to each end: fusiform. Spine: a sharp process: in Coccidae there are two, one each side of each segment of the pygidium. Spiniferous: bearing, or clothed with spines. Spiniform: in the form or shape of a spine.