Metriorrhynchus thoracicus (Fabricius, 1801)

BOCAK, L. & MATSUDA, K., 2003, Review of the immature stages of the family Lycidae (Insecta: Coleoptera), Journal of Natural History 37 (12), pp. 1463-1507 : 1496-1497

Metriorrhynchus thoracicus (Fabricius, 1801)

Differential diagnosis. Metriorrhynchus is defined by the presence of four frontal pronotal processes (figures 105, 106), posterior tergal processes of A6–A8 (figure 107), ventral position of spiracles T2 and dorsal position of spiracles A3. M. thoracicus is characteristic by the shape of tergites A6, which bear only outer process (figure 107), all abdominal terga blackish brown.

Description of mature larva. Body parallel-sided (figures 105–108). Head, pronotum, and legs ferruginous, lateral processes of T2–T3 and A1–A6 black with white apex. Lateral processes of A7–A8 and urogomphi ferruginous, rest of body blackish brown, membranes yellowish-white. Head slightly protruded frontally (figures 101–102). Eyeless. Epicranium continuous, lateral membrane absent, with frontolateral eye incision (figure 88). Mandibles slender, extending almost to apex of maxillary palpi. Mala with two stout bristles. Terga T1–T3 and A1–A9 divided longitudinally by pale membranous median line (figures 105, 107). Pronotum with two sharp, anterior processes in each pronotal sclerites, lateral and posterior processes missing, surface glabrous. Meso- and metathorax with long lateral processes attached by membrane to anterior pleurite. Spiracles of T2 situated ventrally of lateral process. Segments A1–A8 with long, movable process attached to dorsal pleurite (figures 107, 108). Segments A1–A5 lacking tergal posterior processes, A5–A8 with processes of variable length. Segment A9 with long, complex urogomphi (figures 107, 108). Abdominal spiracles on segments A1–A8, situated in dorsal part of ventral pleurite, spiracles A7 on small gibbosity, spiracles A8 on short finger-like process.

Measurements. BL 18.3 mm, WP 1.40 mm, LP 1.37 mm.

Material examined. One mature larva, C. Sulawesi, Boe, 7 km of Pendolo , 750 m, 3.vii.1999, L. Bocak and M. Bocakova ( LMBC) , second mature larva reared in laboratory, pupation 11.viii.1999, female hatched on 26.viii.1999 ( LMBC) , one younger larva ( BL 9.1 mm), from the same locality data ( LMBC) .

Remark. All posterior tergal processes are fully developed in younger instar (size of body 9.1 mm) and they provide reliable diagnostic feature.