A morphological study on the Venom apparatus of the spider Agelena labyrinthica (Araneae, Agelenidae)

Abstract

The morphology of the venom apparatus of the spider Agelena labyrinthica was studied using scanning electron microscopy. The venom apparatus, situated in the anterior of the prosoma, is composed of a pair of chelicerae and venom glands. Each chelicera consists of two parts, a stout basal segment covered by hair, and a movable articulated fang. There are regular, parallel fine grooves on the surface of the cheliceral fang. The venom pore is situated on the subterminal portion of the fang. All of the venom glands are the same size and are shaped like long tubes. Each gland is surrounded by bundles of muscular fibers. Venom is produced in the venom glands, and it is carried by a venom duct passing through the chelicera, exiting from the venom pore during muscular contraction.