Stigmella pseudorobusta Remeikis & Stonis, sp. nov.

Stigmella pseudorobusta Remeikis & Stonis, sp. nov.

(Figs 18, 27, 108–112)

Type material. Holotype: Ƌ, PERU, Dept. Ancash, 35 km SE Huaraz, Cerro Cahuish, Quabrada Pucavado, 9°40'50"S, 77°13'32"W, elevation ca. 4100 m, 15–18.ii.1987, O. Karsholt, genitalia slide no. RA 568Ƌ (ZMUC). Paratypes: 2 Ƌ, 2 ♀, same label data as holotype, genitalia slide nos RA572Ƌ, RA577Ƌ, RA581♀ (ZMUC).

Diagnosis. The combination of a gnathos with closely juxtaposed processes, large apical processes of valva, distally three-lobed uncus, set of 2 large cornuti, and very pale colour of adult scaling distinguishes S. pseudorobusta sp. nov. from all other Stigmella species.

Male (Fig. 108). Forewing length 4.0– 4.5 mm; wingspan 8.6–9.6 mm. Head: palpi cream; frontal tuft yellowish cream to ochre cream with some golden gloss; collar and scape ochreous cream; antenna as half the length of forewing; flagellum with 42 segments, yellowish grey to grey. Thorax, tegula and forewing concolorous with collar and scape, ochreous cream. Forewing without dark scales or fascia; fringe cream; underside of forewing dark brown, at base with elongated cream spots and fuscous scales along costal margin, without androconia. Hindwing pale grey on upper side and underside, with no spots or androconia; its fringe grey cream. Legs yellowish cream, darkened with dark grey on upper side. Abdomen dark grey on upper side and underside; tufts short, brownish grey to dark grey; genital segments cream.

Female. Scaling of head and upper side of forewing paler than in male, mostly whitish cream. Underside of forewing dark brown, at base with distinct elongated cream spots and fuscous scales along costal margin. Abdomen grey cream on underside, with long dark grey lateral tufts; genital segments pale brown.

Male genitalia (Figs 109–111). Capsule longer (385 µm) than wide (190 µm). Vinculum with long rounded lateral lobes and very long ventral plate. Uncus narrowing distally, with three small lobes. Gnathos with two slender, closely juxtaposed caudal processes and laterally widened plate. Valva 210–215 µm long, 60 µm wide, with two very large apical processes and slightly bulged, round (with no pointing corners) inner lobe; transtilla with long triangular corners (sometimes developed as narrow sublateral processes). Juxta membranous, indistinctive. Phallus (Fig. 109) 250 µm long, 75–80 µm wide; vesica with two very large curved cornuti.

Female genitalia (Fig. 112). Total length 1035–1040 µm. Posterior processes slender, slightly longer than anterior ones. Vestibulum narrow. Corpus bursae with heavily folded distal part and round, 415 µm long, 330 µm wide basal part with comb-like pectinations; signa absent. Accessory sac wide but very short; ductus spermathecae with 5.5–6 convolutions. Abdominal apex narrowed but round.

Bionomics. Adults fly in February. Otherwise biology unknown.

Distribution (Figs 18, 27). This species occurs in the high Peruvian Andes (Peru: Ancash Departamento) at altitudes of about 4100 m.

Etymology. The species name is derived from the Stigmella robusta, another large pale-scalled species, occurring in the same area of the Peruvian Andes.