[Electron microscopic study of Haller's organ in the tick, Ixodes persulcatus (Ixodidae)]

Haller's organ consists of the capsule, in which are arranged 7 thin-walled porous olfactory hairs, and an anterior group of sensillae situated in the cuticular recess before the capsule. The anterior group is represented by one thick-walled porous, one conical, two thin and two grooved hairs. The porous hairs are characterized by "plugs", the grooved ones--by a complex system of cavities and tubules. Before the organ there are hairs resembling tactile and gustatory receptors of arthropods, behind the organ there arrange hairs with a system of cavities and tubules. Sensible elements of all sensillae studied are bipolar receptor cells bearing one modified cilium on the surface of peripheral processes. The details of the structure of perceptive and accessory apparatus of the above receptors were investigated.