Givarbela decolorata Penco, Yakovlev, Naydenov & Witt, sp. nov. (Figs 2‒3, 6)

Material. Holotype 1 ♂: Argentina: Santiago del Estero, Coll. A. Breyer (MLP) (Fig. 2). Paratypes: 1 ♂, Argentina: Santiago del Estero, Coll. A. Breyer, (MLP); 1 ♂ (IMZA); Colonia Dora, ix.1940, Coll. A. Breyer, 1 ♂, Prep. Gen. MLP N°7, F.C. Penco (MLP) (Fig. 5); 1 ♂, La Rioja, Patquia, Ago 1939, Coll. A. Breyer (Museum Witt, Munich, Germany, to be deposited in MWM) (Figs. 3; 6); 1 ♂, Guayapa, 26.v.1968, L. Vivoff leg. (MACN).

Description. Male. Head: forehead and vertex brownish, forehead lighter; color of rod of antenna and labial palpus scaling from chocolate to dark brown, tip of labial palpus paler, antenna bipectinate, rami three times as long as diameter of rod of antenna. Thorax covered with long hairs; pronotum hazel colored; dorsally brown, mixed with some gray hairs; fore femur and tibia dark brown; tarsal segments brownish. Color of abdomen as thorax; anal tuft short, paler than the rest of abdomen, spreading but not spatulate. Fore wing: length 10–11 mm, dark grey; costa and basal, post discal and apical areas dark hazel colored; blurry thin pale whitish-grey discal band perpendicular to costa, wide near costa but not reaching it, diagonally crossing wing up to postdiscal area at anal edge, then curving and reaching costa at submarginal area near apex, and becoming thinner and turning lightly inwards at costa; traces of second band at outer edge; outer edge with long fringe, darker over veins. Hind wing: uniform grey-brown with pale costa; veins brownish; blurry and almost indistinguishable pale band from hind edge to cells, in some specimens edge darkened.

Male genitalia. Uncus short, wide, tegumen apically semicircular, trapezoidal; gnathos arms thin, gradually narrowing from base to apices, not fused; gnathos medially reduced, valva apically semicircular, with smooth parallel edges; transtilla uncinate, acute on dorsal edge; juxta triangle-shaped with short lateral processes diverged at right angle; saccus robust, apically mastoid; phallus thin, 3/4 as long as valva, slightly curved in basal third, slightly narrowing apically; distal opening in dorso-apical position, vesica without cornuti.

Female unknown.

Distribution. Argentina: La Rioja and Santiago del Estero provinces (Fig. 8), found in the phytogeographic region of dry Chaco (Burkart et al. 1999).

Diagnosis. G. decolorata is distinguished from the other species of the genus by its external characters as follows: in G. decolorata, the fore wing pattern is blurred, in G. steinbachi and G. drechseli it is contrasted, and by male genitalia: in G. decolorata the valva is parallel-sided; in G. steinbachi and G. drechseli the valva is strongly curved.

Etymology. The name decolorata refers to the faded coloration of wing pattern and to the lack of bright elements.