The emesine assassin bug genus Empicoris (Heteroptera: Reduviidae) from Japan

Abstract

Empicoris Wolff, 1811 belongs to the tribe Ploiariolini of the assassin bug subfamily Emesinae, bearing a particular resemblance to some mosquitoes at first glance in their small body, slender appendages and black and white color pattern. Approximately 70 species from all over the world have been described in this genus (cf. Maldonado Capriles 1990; Putshkov & Putshkov 1996; Putshkov et al. 1999). However, a large number of new species of Empicoris can be expected not only from insufficiently explored regions, such as Southeast Asia, but also from areas where inventories are more or less in progress. An example of the latter is Japan with six described species: Empicoris rubromaculatus (Blackburn, 1889), E. brachystigma (Horvath, 1914), E. minutus Usinger, 1946, E. tesselatoides Wygodzinsky & Usinger, 1960, E. ussuriensis Kanyukova, 1982 and E. toshinobui Ishikawa, 2001. During investigations of my colleagues and of myself, six undescribed species of the genus were recognized from various parts of Japan. Similarity in the general appearance among species of Empicoris often makes their identification difficult. Therefore, it is necessary for accurate identification to use a combination of several morphological characters, such as the structures of head, pronotum, fore legs, hemelytra and male genitalia. Actually, several authors provided detailed descriptions with abundant illustrations (Wygodzinsky 1966; Putshkov et al. 1999; etc.), and their works have been of great help for sound discrimination of the species. However, due to a recent increase in number of indeterminate species mainly from East and Southeast Asia, it is necessary to detect further morphological structures for the distinction of the species. In the course of a careful study of the morphology of Empicoris species, several additional discriminating characters were recognized: the ratio in lengths of the apicalmost blackish annulation and the distal whitish part in the metafemur, the shape of struts in the male, the shape of styloides in the female, etc. In the present paper, the Japanese species of Empicoris are revised, with descriptions of six new species. Diagnoses and illustrations, including male and female genitalia, are provided for all Japanese species. A key to the Japanese species is given. Species-group assignment and the biology of Empicoris in Japan are discussed.