Prosomal glands in Typhlodromus spp. females (Mesostigmata: Phytoseiidae)

A morphological and ultrastructural study on the prosomal glands in females of Typhlodromus exhilaratus Ragusa and T. rhenanoides Athias-Henriot (Mesostigmata: Phytoseiidae) has been conducted by means of light, scanning and transmission electron microscopy. A functional interpretation of the prosomal glands has been proposed in accordance with their anatomy. Our observations have shown: 1) a salivary gland complex composed of two pairs of salivary glands: paired tubular glands located dorso-laterally in the propodosoma and paired racemose glands located latero-ventrally to the previous ones. Each tubular gland is made up of six cells and each racemose gland is made up of six unicellular acini; both glands are connected with the salivary styli; 2) a pair of large glandular organs associated with coxae I, found latero-ventrally at the level of the first and second pair of legs. They discharge their secretion, by way of cuticular ducts, onto the first coxae. The gland cells are characterised by large numbers of mitochondria and stacks of infolded lamellae. These glands are right next to the Malpighian tubules and are assumed to have an osmoregulatory function; 3) a group of cells found under the cheliceral base, above the pharynx and in front of the brain; they are thought to be endocrine cells.