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.