| | Elateriformia (Coleoptera) |
(= Cryptomeridae)
Classification. Polyphaga: Elateriformia.
Distribution. Eucinetidae is a widely distributed family.
Biogeographic regions: Nearctic, Palearctic, Neotropical, Afrotropical, Oriental, Australian.
Biology. Eucinetidae are usually collected in leaf litter, rotten wood, or under the bark of decaying logs. Both adults and larvae are mycetophagous, but some specialize on the spores of slime molds, some feed on the hyphae of Basidiomycetes, and others are associated with various types of decaying plant material.
References
Lawrence, J. F. 1991. Eucinetidae (Eucinetoidea), pp. 364–365. IN: F. W. Stehr (ed.), Immature Insects. Vol. 2. Kendall/Hunt Publishing Co., Dubuque, Iowa.
Lohse, G. A. 1979. 41. Familie: Eucinetidae, p. 264. IN: H. Freude, K. W. Harde and G. A. Lohse (eds.), Die Käfer Mitteleuropas. Band 6. Diversicornia. Goecke & Evers, Krefeld.
Nikitsky, N. B. 1996. New Coleoptera from China. Zoologicheskii Zhurnal 75: 1366–1373 (in Russian; translated in Entomological Review 76: 1231–1237).
Pic, M. 1914. Pars 58. Dascillidae, Helodidae, Eucinetidae. IN: S. Schenkling (ed.), Coleopterorum Catalogus. W. Junk, Berlin, 65 pp.
Vit, S. 1977. Contribution a la connaissance des Eucinetidae (Coleoptera). Revue Suisse de Zoologie 84: 917–935.
Vit, S. 1981. Une nouvelle espèce du genre Tohlezkus Vit de Taiwan (Coleoptera, Eucinetidae). Revue Suisse de Zoologie 88: 769–774.
Vit, S. 1990. Révision des espéces néotropicales du genre Eucinetus Germar (Coleoptera: Eucinetidae). Naturaliste Canadien 117: 103–122.
Vit, S. 1996. Deux espèces nouvelles d'Eucinetidae d;Amerique du Nord particulièrement intéressantes (Coleoptera: Eucinetidae). Elytron 9(1995): 125–137.
Vit, S. 1999. Sur les genres Nycteus Latreille, 1829, et Eucinetus Germar, 1818 (Coleoptera, Eucinetidae). Mitteilungen der Schweizerischen Entomologischen Gesellschaft 72: 387–394.
Vit, S. 2000. Contribution à la connaissance de la famille Eucinetidae (Coleoptera). Revue Suisse de Zoologie 107: 123–138.
Young, D. K. 2000. 39. Eucinetidae. IN: R. H. Arnett, Jr., Jr. and M. C. Thomas (eds.), American Beetles. CRC Press, Gainesville, Florida (in press).
General appearance. Total length 0.8–4 mm. Ratio of body length to greatest body width 1.3–1.85. Body slightly flattened to moderately convex, or strongly convex. Sides of body evenly curved. Body not capable of conglobation (rolling into a ball). 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(s).
Head. Ratio of head length to its greatest width (excluding eyes) greater than 1, or 1 or less. Head width just behind eyes not distinctly greater than prothoracic width. Head moderately to strongly declined; entirely concealed from above by pronotum; without elongate rostrum; not abruptly constricted posteriorly, or abruptly constricted posteriorly to form neck. Temples absent or not closely adpressed to prothorax, or closely adpressed to and abutting prothorax; absent, or shorter than length of eye. Transverse occipital ridge or carina absent, or present. Occiput without stridulatory file. Longitudinal axis of head (from occipital foramen to mouth cavity) 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 (endocarina). Frontal region without median groove or line (endocarina). Head without ocelli.
Compound eyes present, or absent. Eyes not or only slightly protuberant, or strongly protuberant. Vertical diameter of eye less than 2 times horizontal diameter. Eyes coarsely facetted; without interfacetal setae. Ommatidium of the eucone 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. Antennal insertions flush with head capsule or raised, not in fossae. Subantennal groove or cavity on head well developed. Frontoclypeal suture absent or incomplete, or distinctly impressed; straight, slightly curved or angulate, or strongly curved or angulate. Clypeus not laterally emarginate. Anterior edge of clypeus or clypeolabrum straight to convex, or concave to shallowly emarginate. 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. Number of antennomeres 11. Antennae when posteriorly extended reaching beyond middle of prothorax but not middle of elytra. Antennae filiform, or incrassate or clavate, or capitate. Antennomeres 3, 4 or 5 to 10 without or with single rami (uniramose). Antennae at least partly pubescent or with obvious modifications. Antennal modifications beginning on antennomere 5 or beyond. First antennomere (scape) less than 3 times as long as 2nd (pedicel). Antenna not geniculate; without apical club, or with weak apical club. Antennal club 4-segmented; not 5-segmented or with 2nd segment subequal to or larger than 1st; compact; not lamellate; not or slightly serrate; not or slightly flattened; not preceded by a cupule.
Mouthparts. Labrum at least partly visible; free, membranous or separated by suture. Major portion of labrum strongly transverse, or slightly transverse or subquadrate, or distinctly longer than wide. Apex of labrum subtruncate to slightly convex, or strongly convex, narrowly rounded or acute. Labrum moderately to heavily sclerotized, except at base and-or apex. Mouthparts not forming a piercing or sucking tube, or forming a piercing or sucking tube. Mandibles present. Mandible short and broad, or moderately elongate, or very narrow and elongate. Mandibular apex not or slightly and gradually curved mesally, or strongly and abruptly curved mesally; unidentate, truncate or rounded; subacute, bidentate or multidentate. Dorsal part of mandible without tubercle; without setose cavity. Mandible moderately to strongly, more or less evenly sclerotized or pigmented, or much more lightly sclerotized or pigmented at apex; visible in lateral view, or enclosed in mouth cavity or not visible in lateral view. Incisor edge of mandible simple, or with 2 or more teeth. Mandible with well developed mola, or without mola; with well developed prostheca, or without prostheca. Prostheca absent or without articulated, sclerotized process. Inner basal angle of mandible without pubescent process. Maxilla with distinct galea and lacinia. Maxillary lobe(s) not stylet-like, or stylet-like. Apex of galea or maxillary lobe densely setose or spinose, or without or with few setae or spines; without heavily sclerotized teeth or hooks. Lacinia without hook(s) or spine(s), or with apical or subapical hook(s) or spine(s). Apical maxillary palpomere cylindrical to fusiform; at least as wide as or longer than preapical one. Maxillary palp without complex palp organ. Apical labial palpomere cylindrical to fusiform. Ligula undivided or finely cleft.
Prothorax. Ratio of pronotal length to greatest pronotal width 0.25–0.5. Prothorax widest posteriorly. Sides of prothorax more or less straight, or moderately to strongly curved. 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. Greatest prothoracic width not or slightly narrower than greatest elytral width. Lateral pronotal carinae complete; simple; visible for their entire lengths from above; without a raised margin. Lateral portion of prothorax without deep pit. Pronotum without anterolateral callosities. Anterior angles of pronotum distinctly produced forward; produced and broadly rounded or obtusely angulate. Posterior angles of pronotum absent or broadly rounded, or moderately to strongly acute; not produced and acute. Posterior edge of pronotum moderately to strongly produced forming mesal lobe; simple; not or vaguely margined. Discal carinae of pronotum absent. Pronotal disc without paired basal impressions. Pronotum without median longitudinal groove or line. Anterior edge of pronotum simple, without margin. Hypomeron without pit.
Anterior portion of prosternum at midline shorter than prosternal process. Lateral portion of prosternum in front of coxae shorter than mid length of procoxal cavity. Anterior edge of prosternum not produced anteriorly. Prosternum in front of coxae flat to moderately convex. Prosternum in front of coxae without paired lines or carinae. Anterior edge of prosternum without margin; without mesal excavation. Anterolateral or ventrolateral portions of prothorax without cavities or grooves. Prothoracic cavities absent. Prothoracic grooves absent. Prosternal process complete; parallel-sided; flat, concave, or only slightly elevated or curved behind coxae; not extending to mesoventrite. Apex of prosternal process broadly rounded, angulate or truncate. Prosternal process without transverse groove. Accessory (mesal) 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 projecting well below prosternum. Procoxa without or with short concealed lateral extension. Procoxal cavities present, procoxae countersunk. Procoxal cavity strongly transverse. Procoxal cavities at middle narrowly separated. Procoxal cavities externally open; broadly open. Postcoxal projection absent or very short. Procoxal cavities without narrow lateral extensions. Procoxal cavities internally open. Prothoracic trochantin or pleurotrochantin at least partly exposed. Promesothoracic clicking mechanism absent.
Elytra. Elytra present. Ratio of elytral length to greatest elytral width 1.2–1.55. Ratio of elytral length to pronotal length 4–5.8. Elytra apunctate, irregularly punctate, or with 5 or fewer distinct puncture rows or striae, or with more than 5 distinct puncture rows; without scutellary striole. Number elytral puncture rows or striae 10. Sutural stria absent or not deeply impressed near apex, or deeply impressed near apex. Abdominal tergites exposed by elytra none or apex of 1. Elytral apices meeting or almost meeting at the suture. Elytral suture not deflected near apex. Elytral apex without internal interlocking tongue. Epipleuron absent or incomplete; not or gradually narrowed, or abruptly narrowed or excavated. Lateral edge of elytron straight or weakly sinuate.
Pterothorax. Scutellum well developed, or highly reduced, or absent or not visible; not abruptly elevated; anteriorly simple; posteriorly narrowly rounded or acute. Mesoscutum without stridulatory file. Mesoventrite with paired procoxal rests. Paired mesoventral procoxal rests moderately to strongly oblique. Anterior edge of mesoventrite without prosternal rest. Mesoventrite not divided by longitudinal groove or discrimen, or at least partly divided by longitudinal groove or discrimen. Anterior edge of mesoventrite at midline on same plane as metaventrite, or on different plane than metaventrite. Mesoventral cavity small and shallow, or moderately large and shallow. Mesocoxa not conical and projecting. Mesocoxal cavities present, mesocoxae countersunk. Mesocoxal cavities at middle contiguous, or narrowly separated, or moderately to widely 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, or partly or completely fused to mesepisterna. Mesepisterna distinctly separated at midline; without deep pockets. Mesepimeron not visible from above. Mesocoxal cavities open laterally; not partly closed by metepisterna. Mesoventral process extending at least to middle of mesocoxal cavity. Mesometaventral junction absent or a point, or a posteriorly curved, angulate or acute line, or a complex fitting. Mesoventral and metaventral processes at midline separated by gap, groove, or suture. Accessory (mesal) mesocoxal articulation absent.
Metaventral discrimen or median line moderately to very long, or short, or absent. Paired postcoxal lines of metaventrite absent, or present. Postcoxal lines of metaventrite absent, or arched and strongly recurved, or arched but not or slightly recurved. Metaventrite longer than first abdominal ventrite. Postcoxal pits of metaventrite absent. Metaventrite flat to slightly convex. Transverse groove of metaventrite absent. Anterior edge of metaventrite without transverse carina between mesocoxal cavities. Exposed portion of metepisternum short and broad. Metacoxae contiguous or narrowly separated; separated by less than longest coxal diameter; extending laterally to meet elytra or sides of body; completely separated from metaventrite by suture. Metacoxal plates well developed, more or less uniform; not concealing most of basal abdominal ventrite. Metacoxae greatly enlarged; obliquely oriented. Lateral arms of metendosternite moderately to very long. Metendosternal laminae absent. Ventrolateral processes of metendosternite absent or weakly developed, or strongly developed. Anterior process of metendosternite short or absent. Anterior tendons of metendosternite on lateral arms or not apparent. Apical portion of metendosternite not or only slightly emarginate.
Hind wing. Hind wing well developed, or highly reduced or absent; with normal transverse folds. Radial cell of hind wing well developed; shorter and broader. Inner posterior angle formed at base of radial cell right or obtuse. Radial cell forming equilateral triangle. Ratio of length of apical area to total wing length 0.20–0.35. Apical area of hind wing without veins or sclerotizations, or with one or more vague sclerotizations or pigment patches. Medial bar of hind wing not crossed by fold. Free veins in medial area of hind wing 4. Oblongum cell of hind wing absent. Medial fleck of hind wing absent; absent or not partly bisected by a vein. Wedge cell of hind wing reduced, or absent. Apex of wedge cell of hind wing obliquely truncate. Anal lobe of hind wing present. Posterior edge of hind wing without fringe of long hairs.
Legs. Femoral attachment of mid trochanter strongly oblique with base of femur separate from coxa. Mesotrochanter not reduced or concealed from below. Metafemur not much wider than mesofemur. Mesotibia strongly widened, widest at or near apex. Outer edge of mesotibia with distinct teeth or long spines. Outer subapical edge of mesotibia without antenna cleaner. Preapical surfaces of mesotibia without ridges or combs. Outer apical angle of mesotibia simple or slightly produced, without lobe, teeth or spines. Inner apical angle of mesotibia not or slightly produced, without tooth. Mesotibial spurs glabrous or absent; double. Mesotarsus with 5 distinct tarsomeres (pentamerous). Tarsomeres on hind leg at least as many as on mid leg. Tarsomeres on fore leg at least as many as on mid leg. Mesotarsomere 1 well developed and visible. Preapical mesotarsomeres together longer than apical one. Penultimate mesotarsomere not distinctly shorter than antepenultimate. Ventral mesotarsal lobes absent. Mesotarsal claws paired; subequal in length and similar in form and angle of inclination; simple. Appendage on each tarsal claw absent. Mesotarsal claws without setae near base. Mesotarsal empodium present and exposed; absent or with 2 or fewer setae. Outer edge of protibia simple and rounded to carinate but without lobes or teeth, except at apex. Outer apical angle of protibia simple or slightly produced, without lobe, teeth or spines. Inner subapical edge of protibia without antenna cleaner. Protibial spurs double. Articulations of protibial spurs located in same plane. Hind legs without swimming hairs. Preapical surfaces of metatibia without ridges or combs. Metatibial articular area not to only moderately expanded, narrowly oval or oblique. Metatibial spurs double; differing distinctly in length.
Abdomen. Number of abdominal ventrites 5, or 6, or 7. Number of basal ventrites connate two. Abdominal sternite 2 apparently absent. First ventrite not completely divided by metacoxae. Suture between ventrites 1 and 2 distinct. Suture between ventrites 2 and 3 distinct. Ventrite 4 articulated with or connate with both 3 and 5. Postcoxal lines on ventrite 1 absent. Ventrite 1 not much longer than 2. Abdominal process acute or narrowly rounded. Ventrite 5 in female without circular depression. Posterior edge of ventrite 5 not crenulate. Last visible tergite and-or sternite (7 or 8) not forming terminal spine. Tergite and sternite 7 separated by membrane or distinct suture. Subapical abdominal luminous organ absent. Ventrites without setose patches or foveae. Functional spiracles on abdominal segment 8 present. Functional spiracles on abdominal segment 7 present. Functional spiracles on abdominal segment 6 present. Functional spiracles on abdominal segment 5 present. 7th abdominal spiracles located in pleural membrane. 6th abdominal spiracles located in pleural membrane. 5th abdominal spiracles located in pleural membrane. Anterior edge of sternite 8 in male with median strut. Pygidium (sclerotized tergite 7 or 8) more or less horizontal. Anterior edge of sternite 9 in male with median strut (spiculum gastrale). Tergite 9 in male deeply emarginate, or almost completely divided into two parts. Tergite 10 in male well developed and free.
Aedeagus trilobate; symmetrical. Anterior edge of tegmen or phallobase without struts. Parameres individually articulated to phallobase or base of penis, or fused to phallobase or base of penis but free from one another, or partly or entirely fused together but articulated to phallobase; not outwardly hooked. Penis without dorsal and ventral lobes. Anterior edge of penis with paired struts.
Illustrations. • Eucinetus. Eucinetus haemorrhoidalis (Germar). Locality: Denmark. Artist: Victor Hansen. Courtesy of Danmarks Fauna and Zoological Museum, University of Copenhagen. Reference: Hansen 1973. • Bisaya. Bisaya nossidiiformia Reitter. Locality: Iran. Photo: D. McClenaghan. Copyright CSIRO. • Jentozkus. Jentozkus sp. Locality: Mexico. SEM image: E. Seling. Copyright J. F. Lawrence.
The interactive key provides access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, and summaries of attributes within any group of taxa.
Cite this publication as: ‘Lawrence, J.F., Hastings, A.M., Dallwitz, M.J., Paine, T.A., and Zurcher, E.J. 2000 onwards. Elateriformia (Coleoptera). Version: 12th September 2018. delta-intkey.com’.
