Iridothrips iridis (Watson)

(Fig. 17)

Bregmatothrips iridis Watson, 1924: 253 .

Originally described by Watson (1924) from the Netherlands, this species has been recorded widely in Europe in the leaf sheaths of Iris pseudacorus (Mound et al. 1976; Gertsson 2015; Jenser 2013a; Karadjova & Krumov 2015). The original description does not mention the form of the antennal sense cones, but zur Strassen (2003) and Krumov (2013) report these structures as simple. However, Mound et al. (1976) illustrated the antenna of a specimen from Britain with the sense cone clearly forked on segment IV, and incompletely forked on segment III. When longer series of macropterous and micropterous individuals are examined it becomes clear that the sense cones in this species vary (apparently randomly) between individuals from the same population, and can be simple, Y-shaped or V-shaped. Structural variations in this species, including the occasional presence on the head of four pairs of ocellar setae, may possibly be related in some way to variation in the habitat occupied, with the host plants sometimes under water but at other times exposed during dry conditions. A detailed diagnosis of this species is provided by Mound et al. (2018).

Material examined. ENGLAND, Norfolk, Lopham Great Fen, 1 female and 1 male from base of Iris pseudacorus, 18.viii.1966, Pitkin B.R. (in ANIC) .