Elateriformia (Coleoptera) Larvae

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

LYCIDAE

Polyphaga: Elateriformia.

Lycidae are distributed throughout the world, mainly in tropical regions.

Lycid larvae occur in leaf litter and under bark, and they are thought to feed on soft, decaying plant material or possibly slime molds or yeasts.

References

Böving, A. G. and Craighead, F. C. (1931). An illustrated synopsis of the principal larval forms of the order Coleoptera. Entomologica Americana (New Series) 1: 1–351, 125 pls.

Costa, C., Vanin, S. A. and Casari-Chen, S. A. (1988). Larvas de Coleoptera do Brasil, vi + 282 pp. Museu de Zoologia, Universidade de Sao Paulo: Sao Paulo.

Lawrence, J. F. (1991). Lycidae (Cantharoidea), pp 423–424 in Stehr, F. W. (ed.), Immature Insects. Vol. II. Kendall Hunt: Dubuque, Iowa.

Body. Length less than 3 mm to more than 15 mm. Body not broadly ovate and strongly flattened; relatively straight or only slightly curved ventrally; slightly flattened, or strongly flattened; body, as viewed from above elongate and more or less parallel-sided. Vestiture consisting of fine hairs or setae only. Dorsal surfaces more or less heavily pigmented or sclerotized; generally smooth, or generally granulate or tuberculate. Ventral surfaces more or less heavily pigmented, or very lightly pigmented.

Head. Head prognathous or slightly declined; protracted or slightly retracted, or strongly retracted; not concealed from above by prothorax; narrower than thorax; not forming sclerotized, serrate, wedge-like plate. Head capsule not strongly depressed and wedge-like anteriorly; posterior edge of head capsule not or only slightly emarginate. Median epicranial region without longitudinal furrow. Epicranial stem absent or very short. Frontal arms absent. Median endocarina absent or coincident with epicranial stem. Paired endocarinae absent or coincident with frontal arms. Number of stemmata one. Number of antennal segments two. Ratio of antennal length to head width 0.15 to 0.50. Sensorium(a) on preapical antennal segment absent. Antennal base without eversible membranous lobe. Frontoclypeal suture absent or vaguely indicated. Labrum completely fused to head capsule (suture absent); without crenulate emargination. Epipharyngeal rods absent. Mouthparts not forming sucking tube. Mandibles symmetrical; non-opposable, straight or curving laterally at apex; approximate at base and divided longitudinally so that 2 pairs of diverging blades or stylets are formed; narrow and falcate; with open or partly closed groove. Apex of mandible narrow when viewed from in front (parallel or oblique to plane of movement); with single lobe or tooth. Accessory ventral process of mandible absent. Incisor edge of mandible simple. Mesal surface of mandibular base simple or slightly expanded. Mandibular mola absent. Ventral mouthparts retracted. Cardo distinct and sclerotized; undivided; transverse to slightly oblique, or strongly oblique or longitudinal. Cardines or maxillary bases separated from each other by labium. Stipes longer than wide. Maxillary articulating area absent. Maxilla with single, articulated mala. Mala or galea consisting of a single segment. Apex of mala simple, not cleft; or galea rounded or truncate; or galea setose or spinose. Inner apical angle of mala simple. Number of segments in maxillary palp four. First segment of maxillary palp without digitiform appendage. Labium consisting of prementum and postmentum. Mentum, postmentum or labial plate partly or completely fused with maxillae (sutures incomplete or absent). Postmentum or labial plate subquadrate or trapezoidal, with blunt posterior edge. Postmentum or labial plate not divided longitudinally. Ligula absent. Number of segments in labial palp two. Labial palps contiguous or separated by less than width of first palp segment, or separated by more than width of first palp segment. Hypopharyngeal bracon present. Hypopharyngeal sclerome absent. Hypostomal region present (separating labium from thorax). Hypostomal rods present (1 pair); extending to posterior edge of head; diverging posteriorly. Ventral epicranial ridges absent. Gula absent; gular sutures absent. Gula or gular region fused to labium. Occipital foramen not divided by tentorial bridge.

Thorax. Prothorax not or only slightly wider than abdomen; not longer than meso- and metathorax combined. Thoracic terga without patches of asperities; without rows of asperities or carinae. Protergum with 1 or more sclerotized plates. Meso- and metaterga with 1 or more sclerotized plates. Thorax without well-developed lateral tergal processes, or with well-developed lateral tergal processes. Prosternum without armature. Mesocoxae or coxal lobes separated by less than 1 basal coxal diameter to separated by more than 2 basal coxal diameters. Thoracic legs articulated. Number of segments in mesothoracic leg five including pretarsus (claw). Number of segments in mesothoracic leg five or fewer including pretarsus (claw). Legs not highly reduced, more than 0.2 times as long as head width. Metathoracic leg about same size as mesothoracic leg. Meso- and metathoracic legs not forming stridulatory organ. Apical segment of leg acute and claw-like (or consisting of 2 claws). Number of movable pretarsal claws one. Number of setae on pretarsus two. Pretarsal setae lying side by side or obliquely situated. Thoracic spiracles biforous or bilabiate; not placed at ends of spiracular tubes.

Abdomen. Ratio of length of abdomen (without appendages) to length of thorax more than 2.0. Number of visible abdominal segments ten. Abdominal terga not extending laterally beyond edges of sterna, or extending laterally beyond edges of sterna; without patches of asperities; without rows of asperities. Abdomen without well-developed lateral processes, or with 1 pair of lateral processes on most segments, or with 2 pairs of lateral processes (dorsal and ventral) on most segments. Abdominal tergum 3 without transverse dorsal folds or lobes; simple, not divided into transverse dorsal folds or lobes. Paired abdominal glands (openings or porous plates) absent. Dorsal, balloon-like tracheal gills absent. Long and narrow, lateral gills absent. Abdominal sterna without patches of asperities; without rows of asperities. Paired ventral prolegs (or asperity-bearing ampullae) absent. Ventral abdominal gill tufts absent. Abdominal tergum 8 without special armature. Abdominal apex without respiratory chamber. Abdominal segment 9 excluding appendages shorter than segment 8, or as long as or slightly longer than segment 8. Abdominal tergum 9 not forming articulated plate; extending onto ventral surface; without paired processes or urogomphi, or with paired processes or urogomphi; without pit between urogomphi; without median process or terminal disc. Ratio of length of urogomphus to basal width of tergum 9 less than 0.2, or between 0.2 and 1.0. Urogomphi fixed at base; unsegmented; not bifurcate and without accessory processes; posteriorly oriented; separated by between 1 and 2 basal widths, or more than 2 basal widths. Abdominal sternum 9 partly or entirely exposed; simple or apparently absent; not enclosed by sternum 8. Abdominal apex without hinged operculum. Abdominal segment 10 without oval lobes separated by longitudinal groove; concealed from above, sometimes membranous or more or less fused to segment 9; without asperated, tubular holdfast organs. Paired pygopods on segment 10 absent. Anal region posteroventrally oriented, or ventrally oriented. Anal gill tufts absent. Anal hooks absent. Anterior abdominal spiracles biforous or bilabiate. Abdominal spiracles not placed at ends of spiracular tubes. Eighth abdominal spiracles functional and about the same size as others on abdomen; abdominal spiracle 8 lateral or dorsolateral, facing laterally.

Illustrations. • Calopteron.


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. 1995 onwards. Elateriformia (Coleoptera) larvae: descriptions, illustrations, identification, and information retrieval for families and subfamilies. Version: 9th October 2005. http://delta-intkey.com’.

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