Thyanta (Argosoma) excavata Rider, 1991

Rider, D. A. & Chapin, J. B., 1991, Revision Of The Genus Thyanta Stal, 1862 (Heteroptera: Pentatomidae) I. South America, J. New York Entomol. Soc. 99, No. 1, pp. 1-77 : 53-55

Thyanta (Argosoma) excavata Rider , new species

Figs. 265-269, Map 3

Description. Dorsal surface glossy, pale to medium green with reddish-purple transhumeral band, sometimes with reddish-purple coloration on dorsal surface of head, on apex of scutellum, and on apex of coria; punctures concolorous with surface.

Apex of head evenly rounded, outer jugal margins subparallel for middle third of distance from eyes to apex ( Fig. 266). Antennae pale reddish-green, distal two segments slightly darker. Anterolateral margins of pronotum in dorsal view nearly straight; humeral angles obtusely rounded, protruding only slightly beyond margin of adjacent coria ( Fig. 265). Pronotal cicatrices immaculate. Hemelytra uniformly and shallowly punctate; posterior margins nearly straight; costal angles narrowly rounded to angulate, extending to beyond middle of penultimate connexival segments; hemelytral membranes hyaline, lacking brown flecks. Connexiva narrowly exposed, pale green; posterolateral angles of segments minutely marked with black.

Ventral surface glossy, pale yellow to pale green; punctures concolorous with surface; rostrum pale brown with dark brown markings, apical half of segment 4 piceous, reaching onto base of third (second visible) abdominal stemite. Ostiolar canals acuminate apically. Femora and tibiae pale green. Postspiracular black spots absent; posterolateral angles of abdominal segments minutely marked with black.

Mesia! margins of basal plates in caudoventral view nearly straight; posterior margins slightly convex; posteromesial angle of each basal plate distinctly excavated; concavity resulting from excavations in basal plates wider than long, with lateral sides parallel or slightly convergent apically ( Fig. 267); surface ofbasal plates weakly rugose. Sclerotized rod swollen subapically, abruptly narrowed apically ( Fig. 268). Spermathecal duct only slightly swollen and coiled below proximal flange ( Fig. 269). Male unknown.

Measurements. Total length 8.52-8.99 (8.99); total width 5.13-5.68 (5.68); medial length of pronotum 1.66- 1.89 (1.89). Medial length of scutellum 3.53-3.59 (3.59); basal width 3.20-3.42 (3.42); width at distal end offrena 1.21 (1.21). Length ofhead 1.68-1.72 (1.72); width 2.14-2.21 (2.21). Length of segments 1-5 of antennae 0.40 (0.40), 0.85-0.88 (0.85), 0.92-1.09 (1.09), 1. 10, and 1.14, respectively. Length of segments 2-4 of rostrum 1.31-1.44 (1.44), 0.78-0.92 (0.92), and 0.81-0.86 (0.86). respectively.

Holotype. 'i' labeled (a) " COLOMBIA: Dept. Magdalena, Socorpa Mission, Sierra de Perija , m. VIII-5-25- 1968 " (b) "Borys Malkin Collector." Deposited in the American Museum of Natural History (New York) .

Paratype. l 'i'. (a) " Venezuela - AR El Limon 450m l-VI- 1965" (b) "Col. E. Osuna" (c) "Venezuela-Inst Zool.Agricola-Fac.Agronomia Univ, Central" ('i' IZA) .

Distribution. Northern South America ( Map 3).

Comments. Of the three species of Thyanta with distinctly excavated basal plates, T. excavata can be identified by the wider than long concavity in the basal plates which has the lateral sides parallel or slightly convergent; and by the weakly rugose surface of the basal plates.