Oenopiella ventanensis Grazia sp. nov. (Figs. 5 and 34, 44-46, 50, 69; Table 1)

Etymology. The species is named for the type locality.

Type Material. Holotype male: ARGENTINA: Buenos Aires / Parque Tornquist/Sierra de la Ventana / XI- 1996, P. Rebagliati col. (97.101) depositedat Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN), Buenos Aires, Argentina .

Description. Small to medium size (Table 1). Color pale orange (Fig. 5); antennal segments I-III orange, IV-V ferrugineous; legs pale orange. Abdominal venterdensely punctured alonglateral thirds. Mandibular plates shorter than clypeus (Fig. 34). Antennal segment Inot attaining the apexof mandibular plates; length of segment V almost twice that of segment IV. Proportion of antennal segments: I <II <III ≈ IV <V. Margins of bucculae subrectilinear, subtruncate posteriorly. Rostrum attaining metacoxae. Anterior angles of pronotum with small acute projection (Fig. 34). Anterolateral margins of pronotum slightly convex. Scutellum slightly shorter than wide, spatulate at apex, attaining level of posterior half of connexivum of segment V. (Fig. 5).

Male Genitalia. Pygophore oblong (Figs. 44 and 46), dorsal rim uniformly concave over segment X; ventral rim excavated in an open “U,” distinctly projected at middle of base (Figs. 44 and 46, 50); posterolateral angles triangular, projecting posteriorly (Fig. 44); inferior layer of ventral rim strongly projecting ventrally in a half moon-like tubercle in posterior view, larger than in the other species (Figs. 45 and 50). Ventral wall of pygophore with irregular depressions on each side (Fig. 46). Posterior third of segment X with 1 + 1 inconspicuously elevated rounded areas (Figs. 45 and 50).

Distribution. Neotropical Region province (Fig. 69): Pampa (Chacoan subregion).

Comments. O. ventanensis shareswith O. flonensis the mandibular plates subequal in length to the clypeus; with O. punctaria and O. flonensis the anterior angles of the pronotum with an acute projection; and with the other species, except O. flonensis, the slightly convexanterolateralmarginsof thepronotum. Apexof scutellum spatulated with the apical third slightly depressed, and the pygophore ventral rim excavated in an open “U” distinctly projected at middle of base, posterolateral angles triangularly projecting posteriorly, and inferior layer of ventral rim strongly projecting ventrallyin a half moon-like tubercle, visible in posterior view, are unique characters of this species.