Cebrionini
Cebrionini is a tribe of click beetles from the family Elateridae; formerly ranked as a subfamily or family, they are now considered a tribe within the subfamily Elaterinae.
Distribution
Cebrionines live in most parts of the world, but they are absent from Australia and New Zealand. They are particularly abundant in the more arid parts of the Holarctic Region, Nearctic, Palearctic, Neotropical, Afrotropical, and Oriental.Description
Biological
Male cebrionines fly at night and may be attracted to lights. In several genera, including Cebrio, Selonodon and Euthysanius, females are flightless, and other groups are known from males only. All known larvae live in the soil.General
The species are 8–20 mm. in length. Ratio of body length to greatest body width 2.5–4.55. Body slightly flattened to moderately convex. Sides of body not evenly curved. Body not capable of conglobation. Upper surfaces of body clothed with distinct hairs, setae or scales. Vestiture of upper surfaces not including stiff, erect, dark bristles; not including scales or scale-like setae. Upper surfaces of body without deep foveae. Prothorax, metathorax and-or abdomen without extrusible glands. Underside of body without hydrofuge surface.Head
Ratio of head length to its greatest width 1 or less. Head width just behind eyes not distinctly greater than prothoracic width. Head not or slightly declined, or moderately to strongly declined; not entirely concealed from above by pronotum; without elongate rostrum; not abruptly constricted posteriorly. Temples absent or not closely adpressed to prothorax; absent. Transverse occipital ridge or carina absent. Occiput without stridulatory file. Longitudinal axis of head inclined at an angle of less than 45 degrees, or inclined at an angle of 45 to 90 degrees. Frontal region not to moderately, gradually declined. Occipital region without median longitudinal groove or line. Frontal region without median groove or line. Head without ocelli.Eyes
The eyes are strongly protuberant. Vertical diameter of an eye is less than 2 times horizontal diameter. The eyes finely facetted; without interfacetal setae. Ommatidium of the exocone type. Eye entire. Anterior or mesal edge of eye not or only barely emarginate. Posterior edge of eye not or barely emarginate.Antennal insertions exposed from above, or concealed from above; moderately to widely separated. Antennae not borne on raised tubercles. Subantennal groove or cavity on head absent or very weakly developed. Frontoclypeal suture absent or incomplete. Clypeus is not laterally emarginate. Anterior edge of clypeus or clypeolabrum straight to convex. Mouth cavity anteriorly or anteroventrally oriented. Pregular area without laterally opening cavities. Head ventrally without paired subgenal ridges, or with paired subgenal ridges. Head without anteriorly-projecting genal processes. Gular sutures widely separated or absent. Corporotentorium narrow; without median process. Cervical sclerites present.
Antennae
The species have either 11 or 12 antennomeres, dependinding on the gender. Antennae when posteriorly extended not reaching middle of prothorax, or reaching beyond middle of prothorax but not middle of elytra, or reaching beyond middle of elytra but not elytral apices. Antennae filiform, or moniliform, or serrate, or pectinate or bipectinate, or plumose or biplumose. Antennomeres 3, 4 or 5 to 10 without or with single rami. Antennae at least partly pubescent or with obvious modifications. Antennal modifications beginning on antennomere 3, or antennomere 4. First antennomere less than 3 times as long as 2nd, or more than 3 times as long as 2nd. Antenna is not geniculate; without apical club.Mouthparts
is at least partly visible, or concealed beneath clypeus or apparently absent; free, membranous or separated by suture. Major portion of labrum strongly transverse. Apex of labrum subtruncate to slightly convex, or slightly concave or emarginate. Labrum moderately to heavily sclerotized, except at base and-or apex. Mouthparts not forming a piercing or sucking tube. The mandibles are present and are moderately elongated, or very narrow and elongated at the same time. They also are without mola, that have reduced prostheca or doesn't have it at all. Mandibular apex is strongly and abruptly curved mesally and is unidentate, truncate or rounded. The dorsal part of mandible is without tubercle and without setose cavity. The incisor edge of mandible is either simple or have single tooth. Prostheca is absent or without articulated, sclerotized process. Maxilla with distinct galea and lacinia. The maxillary lobe(s) not stylet-like and have a pulp that is without complex organ. The apex of galea or maxillary lobe densely setose or spinose; without heavily sclerotized teeth or hooks. Lacinia without hook or spine. Apical maxillary palpomere cylindrical to fusiform; at least as wide as or longer than preapical one. The apical labial palpomere cylindrical to fusiform. Ligula shallowly to moderately emarginate, or deeply emarginate or bilobed.Prothorax
Ratio of pronotal length to greatest pronotal width 0.4–1.05. Prothorax widest anteriorly, or at middle, or posteriorly. Sides of prothorax more or less straight, or sinuate. Prothorax not laterally compressed to form cavities for legs. Sides of prothorax not or slightly explanate. Base of prothorax not or slightly narrower than elytral bases, or distinctly narrower than elytral bases. Greatest prothoracic width not or slightly narrower than greatest elytral width, or distinctly narrower than greatest elytral width. Lateral pronotal carinae complete, or incomplete, or absent; simple; visible for their entire lengths from above, or not visible for their entire length from above; without a raised margin. Lateral portion of prothorax without deep pit. Pronotum without anterolateral callosities. Anterior angles of pronotum absent or not produced forward; absent, right or rounded, not produced. Posterior angles of pronotum obtuse or right, or moderately to strongly acute; not produced and acute, or strongly produced and narrowly acute. Posterior edge of pronotum more or less straight or evenly rounded, or distinctly sinuate or variously lobed; simple; not or vaguely margined, or with narrow raised margin or bead. Discal carinae of pronotum absent, or located on posterior angles only. Pronotal disc without paired basal impressions. Pronotum without median longitudinal groove or line. Hypomeron without pit. Anterior portion of prosternum at midline shorter than prosternal process, or as long as prosternal process, or longer than prosternal process. Lateral portion of prosternum in front of coxae shorter than mid length of procoxal cavity, or as long as mid length of procoxal cavity, or longer than mid length of procoxal cavity. Anterior edge of prosternum not produced anteriorly, or distinctly produced forming chin piece. Prosternum in front of coxae concave or biconcave, or flat to moderately convex. Prosternum in front of coxae without paired lines or carinae. Anterior edge of prosternum without mesal excavation. Anterolateral or ventrolateral portions of prothorax without cavities or grooves. Prothoracic cavities absent. Prothoracic grooves absent. Prosternal process complete; narrowed apically, or parallel-sided, or gradually expanded and then narrowed; flat, concave, or only slightly elevated or curved behind coxae, or strongly elevated and curved dorsally behind coxae; slightly overlapping mesoventrite, or moderately to strongly overlapping mesoventrite. Apex of prosternal process acute or narrowly rounded. Prosternal process without transverse groove. Accessory procoxal articulation absent. Ventral portion of prothorax on each side with notosternal suture only. Propleuron not extending to anterior edge of prothorax. Propleuron or pleurotrochantin not extending behind coxa. Procoxae not or slightly projecting below prosternum. Procoxa without or with short concealed lateral extension. Procoxal cavity circular or longer than wide. Procoxal cavities at middle narrowly separated, or moderately to widely separated. Procoxal cavities externally open; broadly open. Postcoxal projection absent or very short. Procoxal cavities without narrow lateral extensions, or with narrow lateral extensions. Procoxal cavities internally open, or closed by slender bar. Prothoracic trochantin or pleurotrochantin completely concealed or absent. Promesothoracic clicking mechanism absent, or present.Elytron
The ratio of elytral length to greatest elytral width 1.45–2.85. Ratio of elytral length to pronotal length 1.75–5.75. Elytra apunctate, irregularly punctate, or with 5 or fewer distinct puncture rows or striae, or with more than 5 distinct puncture rows, or with more than 5 distinct impressed striae; without scutellary striolae. Number elytral puncture rows or striae 9. Sutural stria absent or not deeply impressed near apex. Abdominal tergites exposed by elytra none or apex of 1, or most of one, or at least one but less than 2, or at least 2 but less than 3, or 3 or more. Exposed abdominal segments more or less flexible. Elytral apices meeting or almost meeting at the suture, or independently rounded or acute and separated by broad gap. Elytral suture not deflected near apex. Elytral apex without internal interlocking tongue. Epipleuron absent or incomplete, or complete; not or gradually narrowed. Lateral edge of elytron straight or weakly sinuate.Pterothorax. Scutellum well developed; not abruptly elevated, or abruptly elevated; anteriorly simple; posteriorly broadly rounded or obtusely angulate, or truncate. Mesoscutum without stridulatory file. Mesoventrite without paired procoxal rests, or with paired procoxal rests. Paired mesoventral procoxal rests absent, horizontal or slightly oblique, or moderately to strongly oblique. Anterior edge of mesoventrite without prosternal rest. Mesoventrite is not divided by longitudinal groove or discrimen. Anterior edge of mesoventrite at midline on same plane as metaventrite. Mesoventral cavity moderately large and shallow, or moderately to very large and deep. Mesocoxa not conical and projecting, or conical and projecting. Mesocoxal cavities at middle contiguous, or narrowly separated. Mesocoxae separated by less than shortest diameter of coxal cavity. Mesocoxal cavities circular to slightly transverse; not or slightly oblique. Mesoventrite separated by complete sutures from mesepisterna. Mesepisterna is distinctly separated at midline; without deep pockets. Mesepimeron not visible from above. Mesocoxal cavities open laterally; not partly closed by metepisterna. Mesoventral process absent or not extending to middle of mesocoxal cavity. Mesometaventral junction absent or a point, or a posteriorly curved, angulate or acute line, or a complex fitting.