The Subgenus Persicargas (Ixodoidea: Argasidae: Argas)

The female Argas (P.) arboreus coxal organ consists of a nitration chamber, a tubular system, and an accessory gland. The nitration chamber, formed of ramified podocytes with thin, membranous diaphragms between successive pedicels, serves for passive fluid transport. The tubular system is formed of proximal and distal segments consisting of epithelial cells with morphological characteristics of those involved in active transport and fluid osmoregulation. The accessory coxal gland consists of 20–25 alveoli interconnected by alveolar ducts leading to the main coxal duct, which opens to the exterior via the coxal pore (between coxa I and II). Each alveolus contains 1 type of granule-secreting cell, interstitial cells, and cap cells, which may maintain the structural integrity of the alveolus during secretion. The coxal gland secretory cycle is under neural control.