(= Drilidae part).
Classification. Polyphaga: Elateriformia.
Distribution. Species of Diplocladon occur in India, Southeast Asia and the East Indies.
Biogeographic regions: Oriental.
Biology. Diplocladon females are completely larviform and occur with the larvae in soil and litter. They have three small light organs on all trunk segments, except the last two, which have two and one, respectively; these organs emit a greenish-blue light.
Notes. These beetles were placed in Phengodidae by Crowson (1972).
Crowson, R. A. 1972. A review of the classification of Cantharoidea (Coleoptera), with the definition of two new families, Cneoglossidae and Omethidae. Revista de la Universidad de Madrid 21(82): 35–77.
Haneda, Y. 1950. Star-worm in Singapore. Shin Konchu 3: 2–5 (in Japanese).
Harvey, E. N. 1952. Bioluminescence. Academic Press, New York, xvi + 649 pp.
Olivier, E. 1910. Pars 10. Rhagophthalmidae, Drilidae. IN: S. Schenkling (ed.), Coleopterorum Catalogus. W. Junk, Berlin, 10 pp.
Ridley, H. N. 1934. Further observations made in Singapore, upon geckos and distasteful moths and upon a luminous coleopterous, probably rhagophthalmid, larva. Proceedings of the Royal Entomological Society of London 9: 58–60.
Harvey, E. N. 1952. Bioluminescence. Academic Press, New York, xvi + 649 pp.
Wittmer, W. 1944. Catalogue des Drilidae E. Oliv. (Coleoptera-Malacodermata). Revista de la Sociedad Entomológica Argentina 12: 203–221.
General appearance. Total length 25–35 mm. Ratio of body length to greatest body width 5.8–6.5. Body strongly flattened, or slightly flattened to moderately convex. Sides of body not 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. Head width just behind eyes not distinctly greater than prothoracic width. Head not or slightly 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 (from occipital foramen to mouth cavity) inclined at an angle of less than 45 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 absent.
Antennal insertions exposed 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 not laterally emarginate. Anterior edge of clypeus or clypeolabrum deeply emarginate or excavate. Mouth cavity anteriorly or anteroventrally 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 incomplete or absent. Cervical sclerites absent.
Antennae. Number of antennomeres 3. Antennae when posteriorly extended not reaching middle of prothorax. Antennae filiform. Antennomeres 3, 4 or 5 to 10 without or with single rami (uniramose). Antennae at least partly pubescent or with obvious modifications. First antennomere (scape) less than 3 times as long as 2nd (pedicel). Antenna not geniculate; without apical club.
Mouthparts. Labrum concealed beneath clypeus or apparently absent; partly or completely fused to clypeus or frontoclypeus, without or with incomplete suture. Mouthparts not forming a piercing or sucking tube. Mandibles present. Mandible very narrow and elongate. Mandibular apex moderately to strongly, gradually curved mesally, or strongly and abruptly curved mesally; unidentate, truncate or rounded. Dorsal part of mandible without tubercle; without setose cavity. Incisor edge of mandible simple. Mandible without mola; without prostheca. Prostheca absent or without articulated, sclerotized process. Maxilla with single apical lobe. Maxillary lobe(s) not stylet-like. Apex of galea or maxillary lobe without or with few setae or spines; without heavily sclerotized teeth or hooks. 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, or indistinct or absent.
Prothorax. Ratio of pronotal length to greatest pronotal width 0.8–0.93. Prothorax widest posteriorly. Sides of prothorax more or less straight. Prothorax not laterally compressed to form cavities for legs. Sides of prothorax not or slightly explanate. Lateral pronotal carinae complete, or absent; simple; 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; not produced and acute. Posterior edge of pronotum more or less straight or evenly rounded; simple; not or vaguely margined. Discal carinae of pronotum absent. Pronotal disc without paired basal impressions. Pronotum without median longitudinal groove or line, or with median longitudinal groove or line. Hypomeron without pit.
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 mesal excavation. Anterolateral or ventrolateral portions of prothorax without cavities or grooves. Prothoracic cavities absent. Prothoracic grooves absent. Prosternal process absent. Ventral portion of prothorax on each side without sutures or with incomplete notosternal suture. 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 absent, procoxae attached externally. Postcoxal projection absent or very short. Prothoracic trochantin or pleurotrochantin at least partly exposed. Promesothoracic clicking mechanism absent.
Elytra. Elytra absent (anelytrous or larviform). Lateral edge of elytron straight or weakly sinuate.
Pterothorax. Scutellum absent or not visible. Mesoventrite without paired procoxal rests. Paired mesoventral procoxal rests absent, horizontal or slightly oblique. Anterior edge of mesoventrite without prosternal rest. Mesoventrite not divided by longitudinal groove or discrimen. Anterior edge of mesoventrite at midline on same plane as metaventrite. Mesoventral cavity absent. Mesocoxa conical and projecting. Mesocoxal cavities absent, mesocoxae attached externally. Mesoventrite partly or completely fused to mesepisterna. Mesepisterna without deep pockets. Mesepimeron not visible from above.
Metaventral discrimen or median line absent. Paired postcoxal lines of metaventrite absent. Postcoxal lines of metaventrite absent. Metaventrite not 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 very long and narrow or absent. Metacoxae contiguous or narrowly separated; not extending laterally to meet elytra or sides of body; completely separated from metaventrite by suture. Metacoxal plates absent. Metacoxae not greatly enlarged; horizontally oriented. Apical portion of metendosternite not or only slightly emarginate.
Hind wing. Hind wing highly reduced or absent.
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 not strongly widened. 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. Mesotibial spurs glabrous or absent. Mesotarsus with 2 or fewer tarsomeres. Tarsomeres on hind leg at least as many as on mid leg. Tarsomeres on fore leg at least as many as on mid leg. Ventral mesotarsal lobes absent. Mesotarsal claws single; simple. Appendage on each tarsal claw absent. 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 10. Number of basal ventrites connate none. Abdominal sternite 2 visible. 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 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. Functional spiracles on abdominal segment 8 present.
Parameres not outwardly hooked.
Illustrations. • Diplocladon. Diplocladon hasselti Gorham. Locality: Singapore. After Harvey 1952.
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’.