Idioglossa bigemma mascarena, Bippus, 2016

Bippus, Maik, 2016, New or poorly known Microlepidoptera from the Mascarenes (Lepidoptera: Autostichidae, Bedellidae, Batrachedridae, Carposinidae, Epermeniidae, Gelechiidae, Tineidae, Tortricidae), Beiträge Zur Entomologie = Contributions to Entomology 66 (2), pp. 347-370 : 348

Idioglossa bigemma mascarena sspec. nov.

Description (plate 2: figs 5–9): Wingspan 7.5–8.0 mm, head, palpi creamish-white. Antennae creamish white, annealed with brownish-black, filiform in female (fig. 7c), filiform with a subconical projection (fig. 7b) in the male. Eyes blackish. Thorax and abdomen pale-yellowish, abdomen annealed silvery white.

Forwings pale-yellow with two marks of raised silvery scales. A brownish streak from base to 1/ 5 in cell, a brownish V-shaped angle at about 1/4 pointing to tornus, a brownish transverse strike from dorsum to costa at about 3/4 of forewing. Hindwing whitish-silvery with 2 larger pale yellowish fields bordered by 4 metallic, transverse fasciae.

The silvery and brownish scales seem to chip off quite easily on all wings. One of the collected specimens had almost no scales left on the forewing, another one (fig. 6) had perfectly scaled forewings but no scales and markings left on the hindwings.

Male genitalia (plate 2: figs 9–9a): Uncus and gnathos developed, tegumen sclerotized. Valvae with a short transtilla and a long, hooked ampulla. Aedeagus (fig. 9) longer than valvae.

Holotype: 1 male, Réunion, La Possession, alt. 400 m (20°55'37"S / 55°21'45"E).

Paratypes: 3 males, 17-iii-2016 (dissected, slide RE-2529), 22-iv-2016, 23-v-2015, 14-vii-2016, 1 female, 20-ii-2016, same location .

Types will be deposited in the collections of the BMNH, London.

Distribution: La Réunion and Mauritius (subspecies); South Africa (nominal species).

Etymology: Named after the Mascarene islands.

Biology: unknown.

Remarks: The nominal species, Idioglossa bigemma WALSINGHAM, 1881 was described from KwaZulu-Natal / South Africa and recorded by MEYRICK (1910) from a single specimen from Mauritius.

Actually this species gave me a lot of headache. The only specimen conserved in the BMNH seems to be the Mauritian specimen from the Meyrick collection, labelled: Idioglossa bigemma 1/1 Wals. E. Meyrick det. in Meyrick Coll.; Meyrick Coll. B.M. 1938-290; Mauritius NM. 06; NHMUK010304567. I ignore how Meyrick determined the species and if he could see the specimens from the Walsingham collection or not.

Though the specimens collected in Réunion are rather similar to the Mauritian specimen there are some differences in wing markings to the drawing published by Walsingham and they are also much smaller in size (7.5–8.0 mm instead of 10.0 mm). The brownish strike at the base of the forewing was not illustrated by Walsingham and the V-shaped brownish marking at 1/4 of same seems to point into the opposite direction, to the base of the forewing instead. I really wonder if there are not even two different species involved or not.

It will certainly be necessary to study South African specimens to clear the status of this species in the Mascarenes.