DUNLOP J.A.: The epistomo-labral plate and lateral lips in solifuges, pseudoscorpions and mites. In GAJDOŠ P., PEKÁR S. (eds): Proceedings of the 18th European Colloquium of Arachnology, Stará Lesná, 1999. Ekológia (Bratislava), Vol. 19, Supplement 3/2000, p. 67-78. Solifugae and Pseudoscorpiones are accepted by most recent authors as sister taxa, forming a cla-de Haplocnemata. The sister group of Haplocnemata is less certain. Most recent authors have accepted Acari as monophyletic and placed them as sister group of Ricinulei, although a (Ricinulei + Trigonotarbida) relationship has also been proposed. In an attempt to resolve some of these phylogenetic questions, the mouthparts of Solifugae, Pseudoscorpiones and Acari were investi-gated. In these three orders the mouth is covered dorsally by a projecting epistomo-labral plate (a fused epistome and labrum), and ventrolaterally by a pair of finger-like lateral lips, probably derived from the coxae of the pedipalps. This character complex of a epistomo-labral plate + late-ral lips is not seen in other arachnids, although similar, and perhaps homologous structures occur in Opiliones. The epistomo-labral plate + lateral lips are interpreted here as a possible synapo-morphy for (Acari (Solifugae + Pseudoscorpiones)).