Thyanta (Phacidium) cornuta Ruckes

Thyanta (Phacidium) cornuta Ruckes

Figs. 154- 168, Map 4

Thyanta cornuta Ruckes, 1956:66-68 .

Diagnosis. Small to medium; ovate. Dorsal surface olivaceous green; punctures pale brown, sometimes reddish on pronotum and hemelytra.

Outer jugal margins sinuous, not parallel; apex of head narrowly rounded ( Fig. 155). Anterolateral margins ofpronotum angularly concave in dorsal view; humeral angles produced primarily laterad and slightly anterodorsad, spinose ( Fig. 154). Pronotal cicatrices usually immaculate, sometimes vaguely marked with fuscous in each mesial angle; subcalloused line between humeral angles lacking.

Mesia! margins of basal plates in caudoventral view nearly straight; posterior margins sinuously convex; posteromesial angles broadly rounded ( Fig. 166). Sclerotized rod relatively short, swollen subapically, narrowed apical portion elongate ( Fig. 167); spermathecal duct swollen and coiled below proximal flange ( Fig. 168). Posteroventral surface of pygophore arcuately rounded; posterior margin in caudal view sinuously V-shaped, lateral margins distinctly divergent ( Fig. 162). Pygophore in lateral view nearly straight to slightly concave ( Fig. 165); in ventral view, lateral angles slightly prominent, medial portion slightly convex ( Fig. 163). Each paramere robust, apex nearly spinose in medial view ( Fig. 156); rounded in ectal view ( Fig. 158); roughened spiculate area on lateral surface linear, short, near apex ( Fig. 157). Each lateral conjunctiva! lobe of aedeagus with 4-5 spinose diverticula apically and I slightly sclerotized diverticulum ventrally ( Fig. 159); dorsomedial conjunctival lobe apparently absent ( Fig. 160); median penial lobes relatively small, penisfilum moderately large ( Fig. 160).

Types. Ruckes (1956) described T. cornuta from 1 ~ and 2'i?'i? from Brazil. Because the 縠 specimen was missing the pygophore, he designated one of the 'i? specimens holotype. All three specimens were examined and are housed in the American Museum of Natural History (New York).

Distribution. Northern and central South America ( Map 4).

Specimens examined. Eight specimens collected in January, June, July, September, and November, deposited in AMNH, UCV. VENEZUELA: Bolivar: San Cayetano . BOLIVIA: El Beni: Rio Itenez opposite Costa Marques , Brazil . BRAZIL: Chavantina . Mato Grosso: Chapada .

Comments. This species is closely related to T. acuta and T. robusta . It can be separated from those species by the more acuminate humeral angles, and by the characters of the male genitalia. Thyanta acuta has the posterior margin of the pygophore U-shaped with the sides nearly vertical. The posterior margin ofT. cornuta is sinuously V-shaped with the sides not at all approaching the vertical axis of the body. Thyanta robusta has the posterolateral angles double-cone-shaped in ventral and dorsal views; T. cornuta does not.