Cylisticus convexus, een in Nederland zeldzame synantrope landpissebed (Crustacea: Isopoda: Oniscoidea)

Cylisticus convexus, a rare synanthropic woodlouse in The Netherlands (Crustacea: Isopoda: Cylisticidae) Until recently, the occurrence of Cylisticus convexus (De Geer, 1778) in the Netherlands was uncertain. The only certain old record dates from March 1927, when the species was collected at the coal-shed of the Zoological Museum at Amsterdam. During the last years, two specimens have been collected on semi-natural sites. Both were found on a dike, one near Everdingen, in the province of Gelderland, and one near Ritthem, in the province of Zeeland. These are the first records of C. convexus in the field. Yet the species certainly is very rare in The Netherlands. The most important morphological characteristics of the species are described and illustrated. Some information on the ecology and distribution in Europe is provided.