The modes of emission and application of defensive secretions from prosomal scent glands in palpatorid harvestmen were studied using a selection of European species (Arachnida, Opiliones, Palpatores). Twenty-one species of Eupnoi (Phalangiidae and Sclerosomatidae) as well as five species of Dyspnoi (Trogulidae, Nemastomatidae, Ischyropsalididae) were collected at different locations in Austria, Germany, Italy, Macedonia, and Montenegro. Specimens were mechanically irritated by squeezing their bodies with flexible forceps. Emission of secretion from scent glands was documented, and different mechanisms of discharge and application were classified. Results indicate that a rather heterogeneous manner of secretion discharge is realised in Palpatores: While some species emitted secretion in response to minimal mechanical irritation, many other species only reacted to prolonged irritation. In other species no emission of secretion could be induced at all. Moreover, some species frequently responded with enormous amounts of secretion, while other species tended to release rather small amounts. In many cases, different mechanisms of discharge could be observed within one and the same species and even one and the same individual sometimes reacted very heterogeneously to irritation. Results are discussed in terms of the biological roles of secretion: The reluctance to emit secretion in some harvestmen species might reflect a change in the biological role of scent glands from defense to other functions. In a phylogenetic context, only the gross strategies of emission seem to reflect phylogenetic relationships. The ?fine? mechanisms within each gross strategy, by contrast, seem to vary within one and the same species and even within one and the same individual and may be influenced by the filling status of scent glands or the perceived level of irritation.