A review of the genus Chrastoblatta Saussure et Zehntner, 1895 (Dictyoptera: Ectobiidae: Blattellinae)

Abstract

This paper gives a review of the insufficiently studied genus Chrastoblatta Saussure et Zehntner, 1895. The genus Chrastoblatta was described from Madagascar (environs of Antananarivo) and includes two species: Ch. tricolor Saussure et Zehntner, 1895 and Ch. dimidiata (Saussure, 1863). This contribution is based on the study of a series of paralectotypes of Ch. tricolor and syntypes of Ch. dimidiata from The Muséum d’histoire naturelle in Geneva. Additional specimens of Ch. tricolor were found in the collection of the Zoological Institute of the Russian Academy of Sciences in Saint Petersburg. Detailed morphological description of the type species, Ch. tricolor, is given. Particular attention is paid to the structure of the male and female genitalia, which are described for the first time. Chrastoblatta dimidiata is briefly described due to insufficient and damaged material, but it is probably closely related to the type species. The genus Chrastoblatta is characterized by a peculiar structure of the wide and flat head, hind tibiae with concavity at the apex, a distinctly reduced 4th segment of the tarsi, an asymmetrical hypandrium, and robust, curved styli. The presence of not inverted genitalia suggests the placement of Chrastoblatta in the subfamily Blattellinae. At the present time, the differential diagnosis of the genus Chrastoblatta based on characters of the male and female genitalia cannot be compiled due to insufficient knowledge of other Madagascan ectobiid.