Elateriformia (Coleoptera)


J. F. Lawrence, A. M. Hastings, M. J. Dallwitz, T. A. Paine and E. J. Zurcher


(= Dascillidae part; including Eubriidae, Psephenoididae).

Classification. Polyphaga: Elateriformia.

Distribution. Eubrianacine Psephenidae occur in Asia and Africa, western North America and Peru. Eubriinae are widely distributed but most diverse in the Oriental Region. The genus Sclerocyphon is widespread in eastern Australia, and the closely related Tychepsephus occurs in Chile. Psepheninae occur from North America south to Brazil and in Asia. Species of Psephenoides occur in Asia, and Afropsephenoides is known from Africa.

Biogeographic regions: Nearctic, Palearctic, Neotropical, Afrotropical, Oriental, Australian.

Biology. Larval Psephenidae cling to rocks in fast-moving streams and graze on algae; their flattened, disk-like shape has earned them the name "water pennies". Adults, which are short-lived, occur on stream-side vegetation and may be attracted to lights at night.


Artigas, J. N. 1963. Descripcion de la larva de un psefenido Chileno (Coleoptera-Psephenidae). Gayana (Zoologia) 8: 3–8.

Barr, C. B. and P. J. Spangler 1994. Two new synonymies: Alabameubria, Brown, a junior synonym of Dicranopselaphus and Alabameubria starki, a synonym of Dicranopselaphus variegatus (Coleoptera: Psephenidae). Entomological News 105: 299–302.

Basilewsky, P. 1959. Description d'un genre nouveau de Pséphénides du Congo Belge (Coleoptera Psephenidae). Revue de Zoologie et de Botanique Africaines 59: 29–32.

Blackwelder, R. E. 1930. The larva of Eubrianax edwardsi (Lec.) (Coleoptera: Psephenidae). Pan-Pacific Entomologist 6: 139–142.

Bollow, H. 1936. Monographie der palaearktischen Dryopidae, mit Berücksichtigung der eventuell transgredierenden Arten (Col.). Mitteilungen der Münchener Entomologischen Gesellschaft 26: 147–182, figs. 1–61.

Böving, A. G. 1926. The immature stages of Psephenoides gahani, Champ. (Coleoptera: Dryopidae). Transactions of the Entomological Society of London 1926: 381–388, pls. 89–90.

Davis, J. A. 1986. Revision of the Australian Psephenidae (Coleoptera): systematics, phylogeny and historical biogeography. Australian Journal of Zoology Supplementary Series 119: 1–97.

Guérin-Méneville, F. E. 1861. Monographie de nouveau genre Dicranopselaphus et description de quelques autres Insectes Coléopteres appartenant aussi a la famille des Dascillides. Revue et Magasin de Zoologie Pure et Appliquée (2) 13: 531–547, pls. 17–18.

Hinton, H. E. 1939. An inquiry into the natural classification of the Dryopoidea, based partly on a study of their internal anatomy. Transactions of the Royal Entomological Society of London, 87: 133–184,

Hinton, H. E. 1955. On the respiratory adaptations, biology, and taxonomy of the Psephenidae, with notes on some related families (Coleoptera). Proceedings of the Zoological Society of London 125: 543–568.

Hinton, H. E. 1966. Respiratory adaptations of the pupae of beetles of the family Psephenidae. Philosophical Transactions of the Royal Society of London 251: 211–245.

Horn, G. H. 1880. Synopsis of the Dascyllidae of the United States. Transactions of the American Entomological Society 8: 76–115.

Jäch, M. A. and M.-L. Jeng 1995. Nematopsephus gen. n., a new genus of Psephenoidinae from Asia (Coleoptera: Psephenidae). Koleopterologische Rundschau 65: 159–167.

Kiesenwetter, H. von 1874. Die Malacodermen Japans nach dem Ergebnisse der Sammlungen des Herrn. G. Lewis wahrend der Jarhre 1869–1871. Berliner Entomologische Zeitschrift 18: 241–288.

LeConte, J. L. 1874. Descriptions of new Coleoptera chiefly from the Pacific slope of North America. Transactions of the American Entomological Society 5: 43–72.

Lee, C.-F. And M. A. Jäch 1995. Psephenidae: 1. Check list of the Psephenidae of China, pp. 349–354. IN: M. A. Jäch and L. Ji (eds.), Water Beetles of China. Vol. I. Zoologisch-Botanische Gesellschaft in Österreich und Wiener Coleopterologenverein, Vienna.

Lee, C.-F. and M. A. Jäch 1996. Review of the genera Eubria Latreille and Microeubria Lee and Yang (Coleoptera: Psephenidae: Eubriinae). Coleopterists Bulletin 50: 39–51.

Lee, C.-F. and M. Satô 1996. Nipponeubria yoshitomii Lee and Satô, a new species in a new genus of Eubriinae from Japan, with notes on the immature stages and description of the larva of Ectopria opaca (Kiesenwetter) (Coleoptera: Psephenidae). Coleopterists Bulletin 50: 122–134.

Lee, C. F. and P. S. Yang. 1993. A revision of the genus Homoeogenus Waterhouse with notes on the immature stages of H. laurae sp. n. (Coleoptera: Psephenidae: Eubriinae). Systematic Entomology 18: 351–361.

Lee, C. F. and P. S. Yang 1994. Microeubria, a new genus of Oriental Eubriinae (Coleoptera: Psephenidae). Coleopterists Bulletin 48: 325–329.

Lee, C.-F. and P.-S. Yang 1995. Psephenidae: 2. Notes on the genus Homoeogenus Waterhouse, pp. 355–357. IN: M. A. Jäch and L. Ji (eds.), Water Beetles of China. Vol. I. Zoologisch-Botanische Gesellschaft in Österreich und Wiener Coleopterologenverein, Vienna.

Lee, C.-F., M. A. Jäch and P.-S. Yang 1998. Psephenidae: II. Synopsis of Schinostethus Waterhouse, with descriptions of 14 new species (Coleoptera), pp. 303–326. IN: M. A. Jäch and L. Ji (eds.), Water Beetles of China. Vol. II. Zoologisch-Botanische Gesellschaft in Österreich und Wiener Coleopterologenverein, Vienna.

Lee, C.-F., P.-S. Yang and M. Satô 1998. Psephenidae: I. Notes on the East Asian species of Ectopria LeConte (Coleoptera), pp. 295–300. IN: M. A. Jäch and L. Ji (eds.), Water Beetles of China. Vol. II. Zoologisch-Botanische Gesellschaft in Österreich und Wiener Coleopterologenverein, Vienna.

Lewis, G. 1895. On the Dascillidae and malacoderm Coleoptera of Japan. Annals and Magazine of Natural History (6) 16: 98–122, pl. 6.

Lohse, G. A. 1979. 39. Familie: Dascillidae, pp. 249–250. IN: H. Freude, K. W. Harde and G. A. Lohse (eds.), Die Käfer Mitteleuropas. Band 6. Diversicornia. Goecke & Evers, Krefeld.

Pic, M. 1914. Pars 58. Dascillidae, Helodidae, Eucinetidae. IN: S. Schenkling (ed.), Coleopterorum Catalogus. W. Junk, Berlin, 65 pp.

Waterhouse, C. O. 1876. On various new genera and species of Coleoptera. Transactions of the Entomological Society of London 1876: 11–25.

Waterhouse, C. O. 1880. Descriptions of new Coleoptera belonging to the families Psephenidae and Cyphonidae. Cistula Entomologica 2: 563–573.

Zaitzev, P. 1910. Pars 17. Dryopidae, Cyathoceridae, Georyssidae, Heteroceridae. IN: S. Schenkling (ed.), Coleopterorum Catalogus. W. Junk, Berlin, 68 pp.

General appearance. Total length 1.5–8 mm. Ratio of body length to greatest body width 1.35–1.77. Body strongly flattened, or slightly flattened to moderately convex. Sides of body not evenly curved, or 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) 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, or 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, 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, or strongly deflexed, vertical or inflexed at apex only, or strongly deflexed, vertical or inflexed from behind eyes. Occipital region without median longitudinal groove or line (endocarina). Frontal region without median groove or line (endocarina). Head without ocelli.

Compound eyes present. Eyes strongly protuberant. Vertical diameter of eye less than 2 times horizontal diameter. Eyes finely facetted; without interfacetal setae. Ommatidium of the exocone type. Eye entire. Anterior or mesal edge of eye not or only barely emarginate, or shallowly emarginate or slightly divided by canthus. Posterior edge of eye not or barely emarginate.

Antennal insertions exposed from above; moderately to widely separated, or narrowly separated, or closely approximate or contiguous. Antennae not borne on raised tubercles. Subantennal groove or cavity on head absent or very weakly developed, or well developed. Frontoclypeal suture absent or incomplete. Clypeus not laterally emarginate. Anterior edge of clypeus or clypeolabrum straight to convex, or concave to shallowly emarginate. Mouth cavity anteriorly or anteroventrally oriented, or ventrally or posteroventrally oriented. Pregular area without laterally opening cavities. Head ventrally without paired subgenal ridges. Head without anteriorly-projecting genal processes. Gular sutures widely separated or absent. Corporotentorium narrow, or incomplete or absent; 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, or reaching beyond middle of elytra but not elytral apices, or reaching beyond elytral apices. Antennae filiform, or serrate, or pectinate or bipectinate, or plumose or biplumose, or incrassate or clavate. 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 3 (rarely 2). First antennomere (scape) less than 3 times as long as 2nd (pedicel), or more than 3 times as long as 2nd (pedicel). Antenna not geniculate; without apical club.

Mouthparts. Labrum at least partly visible, or concealed beneath clypeus or apparently absent; free, membranous or separated by suture, or partly or completely fused to clypeus or frontoclypeus, without or with incomplete suture. Major portion of labrum strongly transverse, or slightly transverse or subquadrate. 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. Mandibles present. Mandible short and broad. Mandibular apex not or slightly and gradually curved mesally, or moderately to strongly, gradually curved mesally; unidentate, truncate or rounded. Dorsal part of mandible without tubercle; without setose cavity. Mandible enclosed in mouth cavity or not visible in lateral view. Incisor edge of mandible simple. Mandible without mola; without prostheca. Prostheca absent or without articulated, sclerotized process. Maxilla with distinct galea and lacinia, or with single apical lobe. Maxillary lobe(s) not 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). Apical maxillary palpomere cylindrical to fusiform, or slightly expanded and truncate to subtriangular, or securiform to cultriform; at least as wide as or longer than preapical one. Maxillary palp without complex palp organ. Apical labial palpomere cylindrical to fusiform, or slightly to strongly expanded apically. Ligula undivided or finely cleft, or deeply emarginate or bilobed.

Prothorax. Ratio of pronotal length to greatest pronotal width 0.3–0.55. Prothorax widest posteriorly. Sides of prothorax moderately to strongly curved, or straight posteriorly, curved anteriorly. Prothorax not laterally compressed to form cavities for legs. Sides of prothorax not or slightly explanate, or moderately to strongly, horizontally explanate. Base of prothorax not or slightly 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; simple; visible for their entire lengths from above; without a raised margin, or with a raised margin or narrow bead. Lateral portion of prothorax without deep pit. Pronotum without anterolateral callosities. Anterior angles of pronotum absent or not produced forward, or distinctly produced forward; absent, right or rounded, not produced, or produced and broadly rounded or obtusely angulate, or produced and narrowly rounded or acute. Posterior angles of pronotum absent or broadly rounded, or obtuse or right, or moderately to strongly acute; not produced and acute. Posterior edge of pronotum more or less straight or evenly rounded, or moderately to strongly produced forming mesal lobe, or distinctly sinuate or variously lobed; simple, or distinctly crenulate; not or vaguely margined, or with narrow raised margin or bead. Discal carinae of pronotum absent. Pronotal disc without paired basal impressions, or with 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 flat to moderately convex. Prosternum in front of coxae without paired lines or carinae. Anterior edge of prosternum without mesal excavation, or with mesal excavation. Anterolateral or ventrolateral portions of prothorax without cavities or grooves. Prothoracic cavities absent. Prothoracic grooves absent. Prosternal process complete, or incomplete; narrowed apically, or parallel-sided; flat, concave, or only slightly elevated or curved behind coxae, or slightly to strongly elevated but not curved behind; not extending to mesoventrite, or slightly overlapping mesoventrite, or moderately to strongly overlapping mesoventrite. Apex of prosternal process acute or narrowly rounded, or 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 not or slightly projecting below prosternum, or 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 contiguous, or 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. 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 1.05–1.38. Ratio of elytral length to pronotal length 2.8–4.57. Elytra apunctate, irregularly punctate, or with 5 or fewer distinct puncture rows or striae, or with more than 5 distinct impressed striae; without scutellary striole, or with scutellary striole. Number elytral puncture rows or striae 8 or fewer. Sutural stria absent or not deeply impressed near apex. Abdominal tergites exposed by elytra none or apex of 1, or most of one. 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, or crenulate; posteriorly narrowly rounded or acute, or 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, or vertical. 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. Mesoventral cavity absent, or small and shallow, or moderately large and shallow, or moderately to very large and deep. Mesocoxa not conical and projecting, or conical and projecting. Mesocoxal cavities present, mesocoxae countersunk. Mesocoxal cavities at middle 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 absent or not extending to middle of mesocoxal cavity, or extending at least to middle of mesocoxal cavity. Mesometaventral junction absent or a point, or a straight line, or an anteriorly curved, angulate or acute line, or a complex fitting.

Metaventral discrimen or median line moderately to very long. Paired postcoxal lines of metaventrite absent, or present. Postcoxal lines of metaventrite absent. Metaventrite longer than first abdominal ventrite. Postcoxal pits of metaventrite absent. Metaventrite flat to slightly convex, or moderately to strongly convex. Transverse groove of metaventrite present. Anterior edge of metaventrite without transverse carina between mesocoxal cavities. Exposed portion of metepisternum short and broad, or moderately elongate. Metacoxae contiguous or narrowly separated; not extending laterally to meet elytra or sides of body, or extending laterally to meet elytra or sides of body; completely separated from metaventrite by suture. Metacoxal plates well developed, more or less uniform, or well developed mesally, weak laterally, or weakly developed; not concealing most of basal abdominal ventrite. Metacoxae not greatly enlarged; horizontally oriented, or obliquely oriented. Lateral arms of metendosternite short or absent. Metendosternal laminae absent. Ventrolateral processes of metendosternite absent or weakly developed. Anterior process of metendosternite moderately long, or short or absent. Anterior tendons of metendosternite moderately or very close together, or widely separated but not on lateral arms. Apical portion of metendosternite not or only slightly emarginate.

Hind wing. Hind wing well developed; with normal transverse folds. Radial cell of hind wing well developed, or highly reduced or absent; elongate, or shorter and broader, or incomplete or absent. Inner posterior angle formed at base of radial cell right or obtuse, or acute. Radial cell not forming equilateral triangle. Ratio of length of apical area to total wing length 0.20–0.35, or 0.36–0.5. Medial bar of hind wing not crossed by fold. Free veins in medial area of hind wing 5 or 6, or 4, or 3 or fewer. Oblongum cell of hind wing absent. Medial fleck of hind wing absent, or present; absent or not partly bisected by a vein. Wedge cell of hind wing absent. Anal lobe of hind wing absent. Posterior edge of hind wing without fringe of long hairs.

Legs. Femoral attachment of mid trochanter transverse or slightly oblique, or strongly oblique with base of femur separate from coxa. Mesotrochanter not reduced or concealed from below. Metafemur not much wider than mesofemur. Mesotibia not strongly widened. Outer edge of mesotibia simple, crenulate or denticulate. 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. Mesotibial spurs glabrous or absent. 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, or distinctly shorter than antepenultimate. Ventral mesotarsal lobes absent, or on penultimate tarsomere only, or on antepenultimate tarsomere only. Mesotarsal claws paired; subequal in length and similar in form and angle of inclination; simple, or toothed or bifid. Appendage on each tarsal claw absent, or membranous or lightly sclerotized, usually pubescent. Mesotarsal claws without setae near base. Mesotarsal empodium absent or with 2 or fewer setae. Inner subapical edge of protibia without antenna cleaner. Hind legs without swimming hairs. Preapical surfaces of metatibia without ridges or combs.

Abdomen. Number of abdominal ventrites 5, or 6. Number of basal ventrites connate three. 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, or broadly rounded or angulate, or absent. 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. Subapical abdominal luminous organ absent. Ventrites without setose patches or foveae, or with 1 or more setose patches. Functional spiracles on abdominal segment 8 absent. Anterior edge of sternite 8 in male without median strut, or with median strut. Anterior edge of sternite 9 in male without median strut, or with median strut (spiculum gastrale). Tergite 9 in male truncate, or deeply emarginate, or completely fused to tergite 10. Tergite 10 in male well developed and free, or partly fused to tergite 9.

Aedeagus trilobate; symmetrical. Anterior edge of tegmen or phallobase without struts, or with single strut. Parameres individually articulated to phallobase or base of penis; not outwardly hooked. Penis without dorsal and ventral lobes, or with dorsal and ventral lobes. Anterior edge of penis without struts, or with paired struts.

Illustrations. • Eubrianax. Eubrianax edwardsi (LeConte). Locality: North America. Artist: R. E. White. Courtesy of Richard White. Reference: White 1983. • Dicranopselaphus. Dicranopselaphus venosus Champion. Locality: Central America. Reference: Champion 1897. • Eubria. Eubria palustris Germar. Locality: Denmark. Artist: Victor Hansen. Courtesy of Danmarks Fauna and Zoological Museum, University of Copenhagen. Reference: Hansen 1973. • Sclerocyphon. Sclerocyphon sp. Locality: Australia. Artist: F. Nanninga. Copyright CSIRO. Reference: Britton 1970. • Psephenus. Psephenus lecontei (LeConte). Locality: North America. Artist: E. Van Tassell. Courtesy of Dr. Ross Arnett. Reference: Arnett 1963. • Psephenoides. Psephenoides gahani Champion. Locality: India. Artist: A. G. Böving. Reference: Böving 1926.

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 groups 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): descriptions, illustrations, identification, and information retrieval for families and subfamilies. Version: 9th October 2005. http://delta-intkey.com’.