Trigonorhinus rotundatus (LeConte)

Janicki, Julia & Young, Daniel K., 2017, Nemonychidae and Anthribidae of Wisconsin (Coleoptera: Curculionoidea), Insecta Mundi 2017 (579), pp. 1-36 : 20

Trigonorhinus rotundatus (LeConte)

(Fig. 29–30)

Anthribulus rotundatus Leconte 1876: 40 .

Brachytarsoides rotundatus (LeConte) ; Pierce 1930: 31.

Trigonorhinus rotundatus (LeConte) ; Valentine 1957: 9.

Description. Length 1.4–2.4mm (head excluded). Body elongate-ovate, somewhat convex. Integument black to dark reddish-brown, legs light reddish-brown to orange; antennae orange, club dusky. Vestiture consisting of brown setae with scattered patches of fine silvery grey setae. Rostrum moderately prolonged; narrowed apically, medial 1/3 prolonged apically. Frons weakly convex. Pronotum longer than wide, widest at basal angles, gradually narrowed apically, broadly rounded laterally and apically; pronotal hind angles obtuse and rounded; transverse carina basal, very slightly arcuate. Elytral length 1.4X width, 1.5X pronotal length; elytral base slightly wider than base of pronotum, humeral angles rounded; sides evenly and slightly arcuate to broadly rounded apex; striae deep, punctate; interstriae 3.0–4.0X strial width.

Diagnosis. Trigonorhinus rotundatus can be easily recognized as it is the only Trigonorhinus with the pronotal hind angles obsolete (also described as obtuse and rounded). It can also be distinguished by the silvery grey and brown vestiture. It can be distinguished from T. tomentosus by its longer elytra.

Natural history. Blatchley and Leng (1916) recorded this species on the flowers of Vaccinium ; they also stated that it occurs in swampy meadows. This species has also been recorded from smutty grass ( Andropogon spp. ) and ferns ( Valentine 2002). In Wisconsin, it has been found on flowers of huckleberry ( Vaccinium spp. ).

Phenology. In Wisconsin, adults have been collected in June and August.

Collecting methods. The nine Wisconsin specimens examined during this study from five counties represent a NEW STATE RECORD. Most specimens were collected by sweeping.