Trigonops impura (Boheman)

Zimmerman, Elwood C., 1942, Curculionidae of Guam, Insects of Guam I, Honolulu, Hawaii: Bernice P. Bishop Museum, pp. 73-146 : 88-89

6. Trigonops impura (Boheman)

Faust, Stett. Ent. Zeitung 58: 236, 1897 (pl. 1, A).

Celeitthetes inipurus Boheman, Eugenies Resa, 127, 1859.

Derm dark reddish brown to black, quite shiny where exposed, appendages usually more strongly diluted with red; scaling almost uniformly dirty gray with a brownish cast above, scales slightly or conspicuously iridescent; head with green scaling at base; a few green scales scattered on rostrum; prothorax without any distinct markings; elytra colored as the pronotum, concolorous, setae white, gray, or black; scaling on the legs similar to or slightly paler than that of elytra.

Head with front coarsely, deeply and variably punctured, punctures in part concealed by scaling, with a few suberect setae near interocular sulcus; eyes strongly convex, not quite hemispherical, rather strongly protuberant, from slightly more than one half to three fourths as long as distance between their inner margins. Rostrum with area between transrostral carina and basal suture flattened or slightly convex and distinctly depressed below level of carina, about three fourths as long as interocular breadth, laterally convex, with a vague trace of a median carina; apical declivitous part almost flat transversely, shallowly, rather densely punctate, with scattered small green scales. Antennae with scape rather densely squamose, setae erect, varying in length from as long as seven funicular segments to as long as funicle plus first segment of club; funicle with lengths of segments as follows: (1, 1.2) (2, 1.0) (3, 0.7) (4, 0.6) (5, 0.5) (6-7, 0.5); TODO club rather narrowly pointed, almost as long as three preceding funicular segments together, its first segment but slightly longer than the second. Prothorax slightly broader than long, broadest at about middle, rather gently arcuate on sides; coarsely, deeply, densely punctate, punctures variable, either separated by interstices, narrower, as broad as or broader than their diameters or confluent and forming conspicuous longitudinal grooves of chains of punctures; setae arising from intervals, inconspicuous when viewed from directly above, but seen as distinctly erect when viewed from side; interstices densely clothed with rounded, reticulate, iridescent scales. Elytra about three fourths as broad as long, about 2.5 times as long as prothorax, base concave, broadest at about middle, rather evenly rounded laterally to behind middle, thence strongly, slightly concavely, pointedly narrowed to the apex, longitudinal dorsal contour rather evenly convex; striae deep and distinct throughout, their punctures bearing minute, inconspicuous setae; intervals slightly convex on disk, the fifth and sometimes the sixth and seventh, usually more elevated caudad, setae long, conspicuously erect, bristling, only slightly arcuate, discal ones as long and conspicuous as others; squamae dense, flattened, reticulate, appearing granulate and iridescent. Legs with hind femora extending slightly beyond apex of fourth ventrite in female, densely squamose, setae long, fine, slanting to almost erect, broadest part of club twice as broad as base and at about three fourths of distance from base to apex; hind tibiae slightly shorter than femora (5:5.5), almost straight on outer side from base to apical expansion, densely squamose, setae slanting erect. Sternum with distance between anterior margin of prosternum and fore edge of coxal cavity one half that between cavity and hind margin, intercoxal process somewhat more than one third as broad as a coxa, densely squamose, coarsely punctate; mesosternum with side pieces densely squamose, coarsely punctate, almost or quite bare just above coxa, intercoxal process coarsely and densely punctate, squamose, setae erect; metasternum between mid and hind coxae two thirds to four fifths as broad as a mesocoxa, coarsely and densely punctate, squamose on interstices, setae long, erect. Venter with first two ventrites strongly tumid in female, flattened down middle in male, coarsely and densely punctate, densely squamose, but denuded in middle in male, setae long, slanting erect; ventrites 3 and 4 punctate and setose from side to side and with a few scattered squamae; ventrite 5 densely punctate and setose, squamae scattered. Length, 4 mm.; breadth, 2 mm.

Holotype female, labeled " Guam " and "Kinb." in the Naturhistoriska Riksmuseum at Stockholm. One specimen, Mt. Tenjo, May 3, 1936, Usinger ; another, Talofofo, from the plateau, June 17, Swezey .

The conspicuously erect dorsal setae alone will distinguish this small species from all of the Guam Trigonops except T. hirsuta , but the elytral setae are longer than in that species, the antennae are differently formed; this species is smaller, has a different facies, and is not closely allied to T. hirsuta .