Indalia interposita Macià & Ylla & Gastón & Huertas & Bau 2022, comb. nov.

Indalia interposita (Rothschild, 1914) comb. nov.

Original combination: Ilema interposita Rothschild, 1914. Novitates Zoologicae 21: 354.

T. L.: Algeria.

= Eilema interpositella Strand, 1920

Material examined. SPAIN: ALMERÍA: 5 ♂ and 3 ♀, Rambla Granatilla, Sopalmo, 15 m, 20.iv.2005, R. Macià & J. Ylla leg.; 10 ♂ and 6 ♀, Rambla de la Sierra, Tabernas, 452 m, 30SWF59, 3.v.2011, 16.v.2013, 15.v.2015, R. Macià leg. CÁDIZ: 1 ♀, Arcos de la Frontera, 13.ix.1992, J. Gastón leg.; 1 ♀, Puerto de Ojén, 200 m, 28.viii.1991, J. Gastón leg. GRANADA: 8 ♂ and 3 ♀, Barranco de Mazarra, Baza, 727 m, 30SWG25, 14.iv.2015, R. Macià leg.; 1 ♀, La Bernardilla, 100 m, 15.ix.2011, J. Gastón leg.; 6 ♂ and 5 ♀, Bco. Tejos de Castro, Padúl, 1115 m, 30.viii.2011, J. Gastón leg.; MÁLAGA: 2 ♂, Barranco del Pedregal, Mijas, 590 m, 30 SUF5052, 7.v.2019, R. Macià leg.

MOROCCO: 1 ♂ and 1 ♀, 2 Km est de Midar, Driouch (Marroc) 450 m, 30SVD46, 26.v.2017, R. Macià & J. Ylla leg.

Diagnosis. Indalia interposita is easily confused with Indalia uniola, which is very similar externally, especially in old or worn specimens. Indalia interposita is usually slightly larger than Indalia uniola with rather longer, narrow and whitish wings, less ochreous shading and no gloss, which is a characteristic feature of Indalia uniola. For a correct determination of the worn specimens, the genitalia must be examined, but males of Indalia interposita can be easily distinguished by the sound-producing tymbal organ, visible to the naked eye, but absent in the other European species of Eilema sensu lato.

Re-description. Imago (Figs. 21–22). Average wingspan males 25.0 mm (n=10; 18– 3 mm); average wingspan females 23.3 mm (n=10; 16–28 mm).

Genitalia (Fig. 59). Male genitalia: Uncus slender, of medium size, with a pointed and sclerotised tip; valvae ovoid with pointed cucullus; saccular process short and thick with a pointed end slightly curved towards the valva but not reaching the cucullus; clasper absent; juxta triangular, pointed slightly to the top; vinculum short; sacculus right; aedeagus short, cylindrical and voluminous, with a large cornutus. Female genitalia: Size of the anal papillae and the 8th segment, compared with the rest of the genital structure, as in previous species; postvaginal lamella absent and ostium bursae wide and membranous; ductus bursae short and wide, weakly sclerotised; corpus bursa ovoid, signum absent.

Immature stages (Fig. 84). The last instar larva is 15 mm long. Cephalic capsule 1,50 mm wide, with a smooth, light grey vertex with a brown spot on each epicranium. Body with light grey verrucae, with translucent and black setae and a black dorsal line, edged on each side with a broad orange or dark yellow band, touching the D1 and D2 verrucae; a black band between D2 and SD 1 and sides, light grey, with sundry black spots of varying shape. Pupa stylized, with light brown spots, a short clypeus and an abdomen without cremaster. In pupae of males the tip of the wings is open, highlighting the end of the metathoracic legs, but in those of females the tip of the wings is closed. The cocoon under lichens.

Molecular data. The nine specimens successfully sequenced show a high sequence similarity (TN-dist = 0.22% ± 0.12), constituting a strongly supported species clade (PP=1) and a single RESL cluster matching a published BIN (BOLD: ABW9300). As mentioned earlier, this species appears to be closely related to Indalia albicosta and Indalia uniola, with which it shares strong morphological similarities.

Biology. Bivoltine or even trivoltine. Adults in flight from March to October in two or three overlapping generations. Restricted to arid steppe or almost desert biotopes, or pine forests with little understory, at elevations between sea level and 850 m. Both sexes are attracted to artificial light. The larvae feed on lichens that grow on the ground or in bushes, also probably on grasses. In captivity, they accept dry leaves of lettuce (Ylla et al. 2010) and artificial diet.

Distribution (Fig. 105). Species typical of arid and semi-desert areas of Morocco and Algeria. In the Iberian Peninsula, it occurs in characteristic biotopes in the extreme southeast. We are not aware of its presence in Portugal.