The European ant hunters Tracheliodes curvitarsus and T. varus (Hymenoptera: Crabronidae): taxonomy, species discrimination, distribution, and biology

Crabro varus PANZER, 1799 has been originally described from Austria. After the type material has been destroyed, species identity was controversal. Most recently (BITSCH & LECLERCQ 1993, LECLERCQ 1993), the taxon has been interpreted as a species of the ant hunters, genus Tracheliodes, based on a single female collected in Corse, France. New records of Tracheliodes varus from Lower Austria confirm this interpretation; in order to stabilize the species identity, we designated a neotype from the type area, Austria. Tracheliodes varus is most similar to T. curvitarsus (HERRICH-SCHAEFFER, 1841). We present diagnoses and illustrations, describe the variation of colour patterns and give new information on the discrimination of the females of these two sibling species. New records from Austria are reported for Tracheliodes curvitarsus after more than 100 years, and for T. varus after more than 200 years. Trache- liodes curvitarsus is recorded for the first time from Bulgaria and the Czech Republic, T. varus for the first time from the Czech Republic, Slovakia, and Bulgaria. In Laxenburg, Lower Austria, females of T. curvitarsus and T. varus have been found syntopic, both of them hunting workers of the dolichoderine ant Liometopum microcephalum (PANZER, 1798). Based on film sequences, we present first observations on the hunting behaviour of T. varus.