View Image Gallery of Subfamily Collomeninae

This subfamily is based on the New World genus Collomena Möschler, and Kitching & Rawlins (1998) included the Iscadia Walker generic group of Poole (1989) and, with a broader generic content, Holloway (1998) within it. Holloway (1998) indicated that Collomena and the allied New World genus Motya Walker lacked nolid features in their highly modified male genitalia. Hence application of this family-group name within the Nolidae is contentious, and should be assessed further when the early stages of Collomena are known. Mell (1943) included some of the genera and Selepa Moore in his Eligmini.

The Iscadia group has several features that indicate it is monophyletic. The tongue is sometimes reduced or vestigial (New World taxa,
Gadirtha Walker and Plotheia Walker). The forewing is elongate and its reniform is enlarged, with a central patch of raised scales. The male genitalia have the uncus reduced or lost, and the valve has a strengthened costa that often is separated to a greater or lesser degree as a distinct process or arm. The female genitalia have a distinctive signum consisting of a pair of adjacent (fused in Phaeothripa Hampson) sclerotised bands running longitudinally and bearing numerous, small, outwardly directed spines: often there is a similar but much smaller signum opposite and somewhat displaced. The wing venation is of the groundplan type except in Ptisciana Walker and Phaeothripa. The labial palps in several genera (e.g. Gadirtha, Plotheia, Triorbis Hampson and Ptisciana) have this terminal segment long and slender, but it never exceeds the second segment in length. There are no tymbal structures, but the eighth tergite usually has strong apodemes or lobes.

The pupa, where known, has beading on the margin of some abdominal segments and shivers in the cocoon, which also has stridulatory ridges on its interior surface. In two genera (Negritothripa Inoue and Gadirtha) the stridulatory ridges incorporate the characteristically long larval setae (Sugi, 1987). Known larval host-plants include a high proportion of Euphorbiaceae.

The inclusion of several Asian genera in a broad concept of Iscadia by Poole (1989) is not followed here, as clear groupings can be recognised that merit generic status as much as groups in other nolid subfamilies and tribes such as the genera with ‘careine’ male genitalia in the Ariolicini and those with a dark-scaled process to the valve in the Sarrothripini. The relationship of Indo-Australian members of the group to New World Iscadia needs further study. As well as the genera discussed below, the Indo-Australian representation also includes the monotypic tropical Australian Timorodes Meyrick and Ochthophora Turner, with two species shared between Australia and New Guinea. Representation of the group in Africa is not clear, but there is at least one species of Plotheia.

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