Prionus Geoffroy, 1762

Santos-Silva, Antonio, Nearns, Eugenio H. & Swift, Ian P., 2016, Revision of the American species of the genus Prionus Geoffroy, 1762 (Coleoptera, Cerambycidae, Prioninae, Prionini), Zootaxa 4134 (1), pp. 1-103 : 11-12

Prionus Geoffroy, 1762

Prionus Geoffroy, 1762: 198 .

Type species: Cerambyx coriarius Linnaeus, 1758 [designation by Latreille (1810) —(see also Kerzhner, 1991: 123, designation under the plenary powers)].

Size from moderately small (about 18 mm) to large (about 50 mm). Integument from light brown to blackish.

Male. Head from slightly to distinctly elongate behind eyes; dorsal longitudinal sulcus distinct from clypeus to pronotal margin or, at most, only surpassing posterior ocular edge, deep or not between antennal tubercles; dorsal surface coarsely, abundantly punctate, often coarser and more abundant behind upper eye lobes. Eyes large; width interspecific variable; distance between upper eye lobes from distinctly smaller than width of a lobe to distinctly larger. Ocular carina absent or present; when present, usually slightly more elevated near apex. Submentum wellmarked; from slightly to distinctly depressed. Palpi long; labial palpus from distinctly shorter to almost the same length of maxillary palpus; apex of last palpomeres equal in width to about 0.4 times its length, but interspecifically variable when compared with its base: from slightly wider to more than twice or even triple in width. Postclypeus dorsally concave. Mandibles coarsely punctate laterally, shorter than head, usually as long as one-half length or a little longer; outer distal one-third curved forming a right angle, or nearly so, with basal two-thirds (except in P. arenarius ); apex distinctly acute; inner margin without teeth, but as a continuous plate from apex to near base, where there is an abrupt slope; dorsal carina distinct, moderately narrow or wide. Antennae from 12- to 30- segmented (sometimes variable intraspecifically); reaching from just after middle to distal one-fourth; scape from about 1.4 times to twice longer than distal width, short or elongate, shorter than antennomeres III, not or slightly surpassing posterior ocular edge, ventrally depressed; antennomeres III–X imbricate, more so at basal ones, sometimes distinctly bi-flabellate, bilobed or very slightly projected at apex; antennomeres XI often variable in length and shape, including intraspecifically; poriferous system of antennomeres III–XI distinctly finely longitudinally striolate or dull.

Prothorax transverse; antero- and posterolateral angles variable; side with distinct tooth laterally. Pronotum convex, with callosities slightly marked (sometimes absent or almost so), punctation variable, from glabrous to distinctly setose. Prosternum distinctly elevated toward center. Apex of prosternal process rounded, with long, abundant setae. Scutellum glabrous or distinctly setose (sometimes only on lateral base). Elytra glabrous, punctate; longitudinal carina from slightly to very distinct; sutural apex denticulate or, at least, projected. Membranous wings well-developed, with complete venation. Prosternal process surpasses procoxae. Metasternum not reduced, setose. Metepisterna not distinctly narrowed toward apex, about 2.5–3 times longer than wide. Process of ventrite I acute at apex, usually attaining middle of metacoxae. Ventrites glabrous or pubescent (all or part of them); center-distal one-half to one-third of ventrite V depressed, and distal edge emarginated. Legs not distinctly long; pro- and mesotibiae about as long as pro- and mesofemora; metatibiae from 1.2 to 1.4 times longer than metafemora. Tarsi variable in size and shape.

Female: Distance between upper eye lobes from equal to distinctly wider than in males (quite variable intraspecifically). Antennae shorter than in male, not or slightly imbricate at basal antennomeres, 12- to 33- segmented (sometimes variable intraspecifically). Membranous wings as in male. Metasternum about as long as mesofemur to distinctly shorter than mesofemur. Metasternum and metepisterna from glabrous to setose. Ventrites glabrous, or partially setose (mainly I); ventrite V trapezoidal, with posterior edge from not to slightly emarginated.

American distribution: from southern Canada to central Mexico.

Remarks. We believe American Prionus are best divided into two subgenera which can be separated in the key below:

1. Poriferous system of antennomeres not striolate in males; spongy setal pad of metatarsomeres not dense or uniform, and not separated by a well-marked longitudinal sulcus in both sexes................................ Prionus (Homaesthesis) Poriferous system of antennomeres, at least in part, striolate in males; spongy setal pads of metatarsomeres dense, uniform, and separated by a narrow, well-marked longitudinal sulcus in both sexes............................... Prionus (Prionus)