The genus Themonocoris is a small group of peculiar reduviid bugs which until now consisted of four described species distributed in west and central Africa (Fig. 23). Carayon et al. (1958) described the genus and included three species: T. tshikapanus from the Democratic Republic of the Congo (formerly Belgium Congo or Congo-Kinshasa) and Cameroon; T. kinkalanus from the Republic of the Congo (formerly Middle Congo or Congo-Brazzaville), French Equatorial Africa, Equatorial Guinea, Cameroon, Benin (formerly Dahomey) and the Ivory Coast and T. bambesanus from the Democratic Republic of the Congo. Kormilev & van Doesburg (1986) described an additional species, T. aethiopicus from Ethiopia (formerly Abyssinia).
Carayon et al. (1958) placed Themonocoris in the tribe Themonocorini of the subfamily Phymatinae of the family Reduviidae. In their scheme they regard the Themonocorini as primitive phymatines that stand opposed to the other phymatines in the Phymatini. They, however, made no suggestions how to treat the longstanding subfamilies of the former Phymatidae – the Carcinocorinae, Macrocephalinae and Phymatinae.
The arrangement proposed by Carayon et al. (1958) was variously accepted by subsequent authors, but the affiliation of Themonocoris to the Phymatidae and Phymatinae was generally not questioned. China & Miller (1959), Kormilev (1962, 1966: as subfamily Themonocorinae) and Froeschner & Kormilev (1989) retained the Phymatidae at family rank and treated the Themonocorinae with Themonocoris as a fourth subfamily of equal rank to the Carcinocorinae, Macrocephalinae and Phymatinae. Maldonado Capriles (1990) also regarded the Phymatidae as a separate family and did not include it in his Systematic Catalogue of the Reduviidae of the World. Schuh & Slater (1995) regarded the Phymatinae as a subfamily of the Reduviidae and divided it into four tribes that correspond with the subfamilies of Froeschner & Kormilev (1989: 62). Van Doesburg (2004) argued that the placement of Themonocorinae as a reduviid subfamily next to the Phymatinae is an equally acceptable arrangement. In his key, however, he treated the Themonocorini as a tribe of the Phymatinae. Weirauch (2008) in a cladistic analysis of the Reduviiae confirmed the monophyly of the phymatine complex and placement of the Phymatinae as a subfamily recognizing four tribes following Schuh and Slater (1995), as we do in this paper. We are of the opinion that considering the morphological differences, in future the tribe Themonocorini may be best treated as a subfamily of the Reduviidae, next to the Phymatinae. The latter, consisting of the three tribes Carcinocorini, Macrocephalini and Phymatini, are considered to be a concise group characterized by their very high specialized raptorial fore legs and different habitat.
In the present paper a new Themonocoris species from South Africa is described and figured. Notes on its habitat and a key to the Themonocoris species are presented. Finally, the holotypes of T. aethiopicus, T. bambesanus, T. kinkalanus and T. tshikapanus are illustrated (Figs 18-19, 20-21).