Polytoxus marianensis, Usinger, 1946

Usinger, Robert L., 1946, Hemiptera Heteroptera of Guam, Insects of Guam II, Honolulu, Hawaii: Bernice P. Bishop Museum, Bulletin 189, pp. 11-103 : 48-49

41. Polytoxus marianensis , new species ( fig. 10 , a-d).

Small, sparsely, inconspicuously pilose with distinct longitudinal fascia dorsally, relatively short pronotal spines, and distinctive genitalia.

Head distinctly longer than broad across eyes, 37: 27. Antennae five sixths as long as body, proportion of segments one to four as 60: 20: 40: 25.

Pronotum about one third longer, on median line, than head, 53: 37; almost as broad across humeri as long, 50: 53; front lobe elevated, five sixths as long as broad, abruptly narrowed anteriorly, produced into short rounded elevations antero-laterally. Hind lobe about twice as broad across humeri as long on median line, the disk slightly depressed at middle and clothed with subappressed, silky hairs. Lateral spines relatively short, acute, slightly more than one third as long as width of pronotum across humeri, 18: 50; directed laterally and scarcely forward, straight.

Mesonotal spine one third longer than pronotal spines, 25: 18, acute, bent just before middle and directed upwards on apical half. Metanotal spine short, one third as long as mesonotal spine, bluntly rounded at apex and scarcely or only feebly bent upward apically.

Hemelytra reaching tip of abdomen, exposing connexivum moderately at sides.

Legs moderately long, the hind femora just reaching apex of abdomen; hind femora and front tibiae most conspicuously curved.

Male genitalia with claspers three times as long as greatest width, 25: 8, nearly equal in width throughout, slightly and rather evenly curved upward, the apex broad, feebly bent inward and produced on inner dorsal angle as a small, triangular tooth. Posterior process broad at extreme base, abruptly tapering to slender main process and then scarcely tapering to acute apex which is provided with a subapical ventral tooth, thus appearing subtriangular at apex.

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Female with hind angles of last connexival segment not acutely produced, rounded. Pygidial plate rounded dorsally, concealed laterally by side pieces and thus appearing concave at ventrally convergent sides, briefly arcuate ventrally.

Color ochraceous to fulvous with a fuscous fascia well marked at middle of hind lobe of pronotum and thence extending posteriorly along middle to apices of hemelytra. Spines infuscated apically. Head, rostrum and antennae infuscated. Under side of body laterally dark brown to black. Legs pale with dark apices of femora, dark tibiae apically and subbasally, and tarsi; the knees reddish.

Size: male, length 7.65 mm., width (across humeri) 1.3 mm.; female, length 8 mm., width (across humeri) 1.4 mm.

Holotype male, allotype female, and seven paratypes, Inarajan, June 8, Usinger ; four paratypes, same locality, June 25, Usinger ; all taken at bases of rice clumps.

Fifty-six eggs were laid in a glass vial on June 8. When freshly laid, the eggs are white and are covered with a somewhat longitudinally striated, transparent layer of mucus which is drawn out at the micropylar end. The egg is 0.75 mm. long and 0.4 mm. at its greatest width. It is oblong-oval, broadly rounded on one side and scarcely rounded on the other, rounded posteriorly, and with micropylar end carinate around a relatively small cap, the diameter across cap half that of greatest diameter of egg. The chorion is very smooth, polished, without spines and processes, and the egg thus resembles eggs of Reduvius and Triatoma rather than those of Emesinae . Incubation period of eggs, eight days.

P. marianensis is very close to the Philippine fuscovittatus Stal in size and coloration but the pronotal spines in that species, according to Distant (Fauna Brit. India, Rhynch. 2: 219, 1904), are "about as long as pronotum.'' A more detailed comparison is impossible because of the inadequate descriptions of the Philippine species. P. similis China from Samoa is much larger with relatively longer second antenna! segment, more acute and upright metanotal spine, and convex sides of female genital plate. A male from Houailou, New Caledonia, agrees with marianensis in size and in genital characters but the pronotal spines are much smaller, only one seventh as long as width of pronotum across humeri, and the color is quite different, the head, pronotum, and legs being tinged with red. The male genitalia resemble those of selangorensis Miller but that species is smaller with relatively longer pronotal spines.

Figures

FIGURE 10-Polytoxus marianensis: a, lateral view of head and thorax of female; b, dorsal view of head and thorax of female; c, posterior view of female genital segment; d, lateral view of genital capsule of male showing armlike claspers and slender median process.