Acrogonia tenuis sp. nov.

(Figs. 53–74)

Total length. Male holotype 8.5 mm; female paratype 11.0 mm.

Holotype description. Head and thorax. Structural features of head and thorax (Figs. 53–54) much as described above for A. amazonensis sp. nov.

Color. Crown, anterior margin of pronotum and mesonotum (Fig. 53) yellow with irregular reddish-brown or brown marks; disc of pronotum reddish-brown with yellow margins; mesonotum with apex pale yellow. Forewings (Figs. 53–54) reddish-brown, except for membranous portions. Face, lateral and ventral portions of thorax, and legs (Fig. 54) mostly yellow; superior portion of frons and of lateral lobe of pronotum brown.

Male genitalia. Pygofer (Fig. 55), in lateral view, strongly produced posteriorly; with distinct lobe on basiventral portion; disc with dispersed setae. Subgenital plates (Figs. 56–57), in ventral view, subtriangular; basal third slightly expanded laterally and then tapering toward apex; distal portion appearing articulated with remainder of plate (Figs. 56–57); in lateral view, plates short, not extending posteriorly beyond basal half of pygofer; plate surface with scattered setae. Connective (Fig. 58), in dorsal view, T-shaped; stalk with median keel, apex distinctly expanded. Style (Fig. 58), in dorsal view, extending posteriorly much farther than apex of connective; preapical lobe distinct, bearing few setae; apical portion directed outward; apex acute. Aedeagus (Figs. 59–60) symmetrical; shaft (Fig. 59), in lateral view, elongate, sinuate, distal half slender and slightly curved dorsally, median third with small dentiform process; in ventral view, apex (Fig. 60) with pair of tiny processes directed laterally; aedeagal base with pair of conspicuous basal processes with their apices curved anterodorsally. Anal tube (Fig. 61) without processes.

Female. Genitalia. Sternite VII (Fig. 62), in ventral view, with basal, median bifurcated structure (BBS) and pair of lateral, narrow elongate projections (LPR). Pygofer (Fig. 63), in lateral view, strongly produced posteriorly; apex obtuse; disc with dispersed setae. First valvifers (Fig. 64), in lateral view, elongate, subrectangular. First valvulae (Fig. 64), in lateral view, with conspicuous basiventral lobe (BLB; Fig. 65); with projection on median portion of ventral margin (VPR); apex acute, dentiform (Figs. 64, 69); setae distributed on ventral margin of basal third and basiventral lobe; ventral interlocking device located on basal half of blade; dorsal sculptured area (Figs. 66–67, 69) extending from basal portion of blade to apex, formed mostly by scale-like process arranged in oblique lines; ventral sculptured area (Fig. 68) restricted to apical portion of blade, formed mostly by scale-like processes. Second valvulae (Fig. 70), in lateral view, with dorsal margin slightly convex; ventral margin almost straight; preapical prominence strong (Fig. 74); apex obtuse; about 27 teeth (Figs. 70–74) distributed on dorsal expanded portion of blade; most teeth (Fig. 72) triangular, armed with denticles, with ascending portion (= anterior edge) short, descending portion (= posterior edge) elongate; blade with ducts (Figs. 72–73) extending to apical portion and to teeth or terminating below latter; few basal teeth (Fig. 71) without ducts. Gonoplacs, in lateral view, with basal half narrow and apical half distinctly expanded; apex obtuse.

Etymology. The name of the new species, tenuis, refers to the slender apical half of the aedeagus (Figs. 59– 60).

Type material. Holotype: male, “Sinop—MT [state of Mato Grosso]\ X.1976 \ M. [ Moacir] Alvarenga col.” (DZUP) . Paratype: one female, same data as holotype (DZUP) .