Thyanta (Argosoma) vadosa 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 : 55-57

Thyanta (Argosoma) vadosa Rider , new species

Figs. 270-284, Map 3

Description. Ovate; dorsal surface green to pale brown; some interstitial areas of pronotum, scutellum, and elytra pale yellow; sometimes marked with reddish-purple between humeral angles, on apex of scutellum, and on tylus and vertex of head. Punctures green to pale brown.

Apex ofhead arcuately rounded; outerjugal margins sinuous, subparallel formiddle third of distance from eyes to apex ( Fig. 271); vertex convex. Antennae pale green to brown, apical portions of distal 3 segments reddish to dark brown. Anterolateral margins of pronotum in dorsal view straight to slightly concave; humeral angles rounded to angulate, often projecting beyond base ofadjacent coria ( Fig. 270). Pronotal cicatrices immaculate. Punctation becoming sparse medially, central portion of pronotal disc subcalloused. Posterior third of pronotum often darker than rest of pronotum. Basal disc of scutellum tumid. Hemelytra glossy, punctures shallow, uniformly distributed; costal angles narrowly rounded to angulate, reaching to middle of penultimate connexival segments. Membranes hyaline, with a few obsolescent brown flecks distally. Connexiva narrowly exposed, green to pale brown, posterolateral angles of segments piceous.

Venter pale yellow to green; punctures concolorous. Femora and tibiae pale brown to green, tarsal segments and apex of each tibia darker. Rostrum green to pale brown, distal half of segment 4 black, reaching onto base of abdomen. Ostiolar canals acuminate apically. Postspiracular black spots lacking (except in brown form); posterolateral angles of abdominal sternites marked with piceous, sometimes only minutely so.

Mesia! margins of basal plates in caudoventral view straight to slightly convex; posterior margins slightly convex; posteromesial angle of each basal plate broadly and shallowly emarginate, lateral sides of concavity resulting from excavations in basal plates divergent, not parallel ( Fig. 282). Distal end of sclerotized rod swollen subapically, narrowed apically ( Fig. 283); spermathecal duct moderately swollen and coiled below proximal flange ( Fig. 284). Posterior margin of pygophore in caudal view broadly U-shaped, medial portion straight to slightly convex ( Fig. 278); chinlike protuberance appearing relatively narrow in ventral and dorsal views ( Figs. 278, 279); pygophore deeply emarginate in lateral view ( Fig. 281). Each paramere with concave surface oriented mediad; from ectal view, apex angling gently mesad ( Fig. 274); from medial view, apex acutely angulate, straight or bending slightly ventrad ( Fig. 272); roughened spiculate area on lateral surface ovoid ( Fig. 273). Each lateral conjunctival lobe ofaedeagus without sclerotized diverticula ( Fig. 277); dorsomedial conjunctival lobe weakly developed ( Fig. 276); median penial lobes spatulate ( Fig. 275).

Measurements. Total length 7.57-10.17 (8.04); total width 4.73-6.15 (5.05); medial length of pronotum l.60-1.88 (l.66). Medial length of scutellum 3.15-4.08 (3.42); basal width 2.98-3.75 (3.20); width at distal end offrena 1.14-1.32 (1.18). Length ofhead 1.59-1.86 (l.64); width 2.12-2.39 (2.21). Length of segments 1-5 ofantennae 0.44-0.52 (0.44), 0.81 --0.96 (0.85), 0.96-1.14 (1.07), 1.14-1.25 (1.14), and l.07-1.18 (1.07), respectively. Length of segments 2-4 of rostrum l.21 -1.44 (1.29), 0.74-0.88 (0. 77), and 0.70--0.81 (0. 74), respectively.

Holotype. & labeled (a) " Santa Margarita Hill , TRINIDAD May, 1959" (b) "Taken at light." Deposited in the Canadian National Collection, Ottawa, Canada .

Paratypes. 5&&, 522. " Trinidad, W.I. Sept. 58 - June 59 " (& CNC) ; (a) " Bejucal , Trinidad,BWI, 24 Oct. 1945 " (b) " E. McC. Callan Collector " (c) "on inflorescences of Cordia macrostachya" (& USNM) ; (a) " Trinidad, 8 II '52, F. Schrader, &, 776" (b) " Thyanta pseudocasta (Bit.) cp. with TYPE, det. Ruckes" (& AMNH); " TOBAGO: W. I. 17-19 July 1964 J.M. Capriles" (& USNM) ; (a) " TRINIDAD: CuREPE , SANTA MARGARITA CIRCULAR Ro. 5-III-76 F. D. BENNETT BLACKLIGHT TRAP" (b) "CJ Drake Coll. 1956" (& USNM) ; TRINIDAD: Curepe, Santa Margarita Circular Rd. III- 19- 75 - X- 1971 F. D. Bennett, Blacklight trap" (222 ARH) ; (a) " St. Augustine , Trinidad, BWI, Sept. 15, 1944 " (b) " I. E. Kirby Coll." (c) "I.CT.A. 12953" (2 USNM) ; (a) " Trinidad, 16 I '52, F. Schrader, 702" (b) " Thyanta maculata (Fabr.), det H. Ruckes" (2 AMNH) ; and " VENEWELA: Lara; Yacambu National Park l 3kmSE Sanare, 4800 feet, 4-7 III 1978,blacklight, cloud forest,J.B.Heppner" (2 USNM) .

Distribution. Trinidad and Tobago; Venezuela ( Map 3).

Comments. The shape of the emargination in the posteromesial angle of each basal plate of the female is distinctive. Thyanta emarginata and T. excavata both have the posteromesial angles of the basal plates deeply emarginate, but the sides of the resulting concavity are nearly parallel, not divergent as in T. vadosa. The male genitalia are also distinctive. Thyanta vadosa is the only species with the apex of each paramere not only acutely angulate (almost acuminate) but also straight or bending slightly ventrad. All other species in the subgenus Argosoma that have the apex of each paramere acute to acuminate also have the apex bending dorsad.

Etymology. Vadosa is the Latin word for shallow. This species is named for the distinct but shallow excavation of the posteromesial angle of each basal plate.