Fig. 10
Ultrastructure of epidermal glands with stalked ducts (intermediary and secretory cells, a-e), small solitary epidermal glands (d, f), and sensilla trichodea (g, h) located on the male ultimate leg of Haplophilus subterraneus as depicted from TEM. a Transition zone of canal cell and intermediary cell. Note that the duct surrounded by the canal cell is lined by a cuticular intima. Cytoplasmic details of a secretory cell (not necessarily of the same gland) are visible to the lower left. b Tangential section of both secretory cells (reservoirs not cut) encompassed by canal cell with extremely electron-dense and barely contrasted cytoplasmic content, the cuticle-lined duct is cross-cut surrounded by microvilli formed by canal cell. Intermediary cell not visible. c Apex of both strongly granulated secretory cells more proximal than in (b). Note that both reservoirs (asterisks) converge to form the duct (non-cuticularized at this level). d and e Section of apical region of both secretory cells located between (b) and (c) demonstrating the dichotomic structure of the most proximal duct region (region magnified in inset (e), marked in (d) by dashed box). Cytoplasm of intermediary cell barely distinguishable from surrounding cells. f Canal cell of a solitary flexo-canal epidermal gland in cross-section. Note the extensive system of microvilliform projections, which project through the expanded central cavity and make terminate at the outer surface of the duct wall. g and h Sensillum trichodeum slightly above (g) and below (h) the socket level. Sensillum shown in (g) shows the basal aspect of the shaft wall cuticle, 10 small chemoreceptive dendritic outer segments, and a single tubular body. Sensillum shown in (h) included only two chemoreceptive dendritic outer segments, but the full set of three tubular bodies. Abbreviations: cca central cavity, cu cuticle, cc canal cell (of a flexo-canal epidermal gland), cde chemoreceptive dendritic outer segments, ds dendritic sheath, du duct, epc epidermal cell, gr secretory granule, ic intermediary cell, in cuticular intima, isl inner sensillum lymph space, mi mitochondrion/mitochondria (cristae type), mv microvilli, nucc nucleus of a canal cell, pro microvilliform projection, rER swollen cisternal of the rough endoplasmatic reticulum, res reservoir, rmv ring of microvilli (secretory cell), scrceg secretory cell of a recto-canal epidermal gland, sc secretory cell (of epidermal gland with stalked duct), sc1 secretory cell 1 (of epidermal gland with stalked duct), sc2 secretory cell 2 (of epidermal gland with stalked duct), sf socket fibres, sl extremely electron-dense outer layer (secretion layer), swc shaft wall cuticle, tb tubular body/bodies