Mecinus Germar, 1821

Gosik, Rafal, Skuhrovec, Jiri, Caldara, Roberto & Tosevski, Ivo, 2020, Immature stages of Palearctic Mecinus species (Coleoptera, Curculionidae, Curculioninae): morphological characters diagnostic at genus and species levels, ZooKeys 939, pp. 87-165 : 87

Genus Mecinus Germar, 1821

Description of the mature larva

(L3). Measurements (in mm). Body length: 1.66-4.75. Body width (metathorax or abdominal segments I-II) 0.37-1.25. Head width: 0.30-0.66.

Body distinctly white to yellow. Body curved, slender, rounded in cross section. Setae on body thin, in different colouration, distinctly different in length; piliform, integument often with some asperities. Prothorax slightly smaller than meso- and metathorax. Spiracle placed between the pro- and mesothorax (see e.g., Gosik et al. 2016). Abdominal segments I-III(VI) of almost equal length, next abdominal segments decreasing gradually to the terminal parts of the body. Abdominal segment X reduced to three or four anal lobes of unequal size. Anus located terminally. Thoracic spiracles uni- or bicameral, eight abdominal spiracles unicameral, all spiracles functional, close to anterior margin of segment. Prothorax with eight to eleven prns; two ps; and one eus. Mesothorax with one prs, two or three pds; one or two as; three ss; one eps; one ps; and one eus. Chaetotaxy of metathorax almost identical to that of mesothorax. Each pedal area of thoracic segments well separated, with three to six pda. Abdominal segments I-VIII with one prs; three or four pds; two or three ss; two long eps; one ps; one lsts; and two eus. Abdominal segment IX with two to four ds; one or two ps; and two sts. Abdominal segment X without or with up to two minute ts.

Head capsule yellow to pale brown, rounded or flattened laterally, endocarinal line distinct, half or more than half the length of frons. Frontal sutures extended to antennae. One or two stemmata (st), anterior stemma in the form of a pigmented spot with convex cornea. Dorsum of the epicranium with five setae; des1 located in the central part of epicranium, des2 lateral, des3 located anteriorly on epicranium close to frontal suture, des4 often medially, des5 located anterolaterally. Frons with three to five fs, fs1 sometimes absent, fs2 absent except one exception; fs4 and fs5 subequal. Head with two les, one or two ves, and one to five pes. Antennae located at the end of the frontal suture on each side, membranous and distinctly convex basal article bearing three or four sensilla and a conical sensorium, the later elongated, narrow. Clypeus trapezium-shaped, with one or two cls, and one sensillum (clss); all very close to margin with frons. Labrum with three lms; anterior margin bisinuated; lrs1 placed posteromedially, lrs2 anteromedially, lrs3 posterolaterally. Epipharynx with three finger-like als; with two or three ams; and one or two mes; labral rods (lr) distinct, kidney-shaped. Mandibles distinctly broad, bifid, teeth of unequal height; slightly truncate; both setae piliform. Maxilla stipes with one stps, two pfs and one short to minute mbs; mala with six or seven finger-like dms; four or five vms; all vms distinctly shorter than dms. Maxillary palpi with two palpomeres; basal palpomere with one short mxps and two sensilla; distal palpomere with one sensillum and a group of microcuticular apical processes. Prelabium various in shape, with one prms; ligula with sinuate margin and two or three ligs; premental sclerite well sclerotised but without anterior and posterior extensions, U-shaped or cup-like. Labial palpi with one or two palpomeres; each of the palpomeres with one sensillum, distal palpomere with cuticular apical processes. Postlabium with three pms: pms1 usually the shortest, placed anteromedially or anterolaterally, pms2 the longest, placed laterally, and pms3 short or medium, placed posterolaterally.

Description of pupa.

Measurements (in mm). Head width: 0.28-0.75. Body width: 0.90-2.15. Body length: 1.20-5.00.

Body stout or elongate; normally white, but sometimes yellowish; cuticle smooth. Rostrum various in length, from two to five times as long as wide. Antennae short or elongate. Pronotum 1.1-2.2 times as wide as long. Meso- and metanotum often equal in length. Abdominal segments I-(IV)VII of equal length; segment VIII almost semicircle, segment IX distinctly reduced. Spiracles on abdominal segments placed dorsolaterally; on segments I-V functional, on segment VI atrophied on next ones invisible. Urogomphi (ur) short or elongate.

Chaetotaxy often well developed, but sometimes almost invisible. Head capsule without or with one vs, without or with up to two sos, without or with up to two os. Rostrum without or with up to two rs, and without or with one pas. Pronotum without or with up to two as, without or with one ds, one or two sls, without or with up to two ls, and two to four pls. Dorsal parts of meso- and metathorax with two or three setae. Apex of femora normally with one short fes. Abdominal segments I-VIII without or with up to two setae laterally and without or with up to three setae ventrally. Dorsal parts of abdominal segments I-VII with three to seven setae; abdominal segment VIII with three to six setae dorsally. Abdominal segment IX without or with up to four micro-setae ventrally.