Philopedon plagiatum

Gosik, Rafal, Sprick, Peter & Morris, Michael G., 2019, Descriptions of immature stages of four species of the genera Graptus, Peritelus, Philopedon, and Tanymecus and larval instar determination in Tanymecus (Coleoptera, Curculionidae, Entiminae), ZooKeys 813, pp. 111-150 : 123-126

Philopedon plagiatum

Specimens examined.

6 premature larvae: Germany, Niedersachsen, Hannover-Vahrenheide, Kugelfangtrift, nutrient-poor sandy grassland, collected at sparsely grown sites under Plantago lanceolata , 02.10.2011: 3 ex., 11.11.2011: 3 ex.

3 mature larvae: same site as before, 02.10.2011: 1 ex., 11.11.2011: 1 ex.; Denmark, Syddanmark, Emmerlev Klev near Højer, moraine at the sandy sea shore of the North Sea, collected on 13.08.2015: 1 ex., between the roots of Plantago maritima L. subsp. maritima , very probably; P. lanceolata was also present nearby.

Description of the mature larva.

Body length: 6.5-8.2 mm, body width at the widest part (level of first abdominal segment): 2.4-3.4 mm, head width: 0.97-1.03 mm, head height: 0.75-0.83 mm.

Body (Figs 7-9). Slender, elongate, slightly narrowed bilaterally dorso-ventrally. Prothorax slightly smaller than mesothorax; metathorax as wide as mesothorax. Abdominal segments 1-7 of almost equal length. Abdominal segment 8 wide, flattened posteriorly, with conical lateral lobes. Abdominal segment 9 strongly reduced, consisting of 4 well-isolated lobes, ventral almost rounded, lateral conical, dorsal semicircular. Abdominal segment 10 consists of 4 anal lobes of almost equal size. Anus located ter minally, covered by lobes of abdominal segment 9. Apical parts of lateral lobes of the segments 6-8 and all lobes of segment 9 darkly sclerotized (Figs 46-48). Spiracles (of thoracic and abdominal segments 1-8) annular. Chaetotaxy well developed, setae capilliform, variable in length, yellowish to brown. Each side of prothorax (Fig. 44) with 9 prns of unequal length, placed on the weakly sclerotized pronotal sclerite; 2 ps and 1 eus very short. Meso- and metathorax (Fig. 44) on each side with 1 moderately long prs and 4 pds, variable in length (first, second and fourth short, third moderately long), 2 short as, 3 minute (various in length) ss, 1 moderately long eps, 1 short ps and 1 eus. Each pedal area of thoracic segments with 9 pda, variable in length. Abd. segment 1-8 (Figs 45-48) on each side with 1 short prs and 5 pds, almost equal in length, arranged along the posterior margin of each segment, 1 minute and 1 long ss (segment 8 with 1 minute ss only), 4 eps (segment 6 with 3 eps, segments 7 and 8 with 2 eps) and 2 ps, equal in length, 1 lsts and 2 short eus. Abdominal setae increase slightly and gradually from segment 1 to 8. Abd. segment 9 (Figs 46-48) on each side with 2 moderately long ds, located near the posterior margin of the segment, 1 moderately long ps and 2 short sts. Anal lobes without setae.

Head (Fig. 49). Greyish to light yellow, suboval, slightly oblate bilaterally; frontal suture almost invisible, endocarina absent. Setae on head capilliform; des1, 2, 3, 5 long, equal in length, des4 very short; des1 and des2 located in the central part of epicranium, des3 and des4 placed on epicranium close to des3, des5 located anterolaterally; fs4, 5 equal in length, fs3 very short; fs3 placed medially, fs4 located anteromedially, fs5 anterolaterally, close to epistome; les1 and les2 equal in length, slightly shorter than des1. Single ves moderately long. Postepicranial area with 4 very short pes (Fig. 49). Antenna (Figs 50, 51) located at the end of frontal suture; antennal segment membranous, bearing sensorium usually cushion-like, truncate at apex (Se) (Fig. 50) or occasionally conical-like (Fig. 51), and 5 sensilla: 2 ampullacea (sa) and 3 basiconica (sb). Labrum (regular) (Figs 52, 53) (deformed) (Fig. 54) almost semicircular, anterior margin doubly sinuate; 3 pairs of lrs almost equal in length; lrs1 placed medially, lrs2 anteromedially, lrs3 anterolaterally. Clypeus (Figs 52, 53) trapezoid, anterior margin of clypeus straight; 2 pairs of cls almost as long aslrs–cls 1 located posterolaterally, cls2 posteromedially; clss clearly visible placed posteriorly, between cls. Epipharynx (Fig. 53) with 3 pairs of finger-shaped als of various lengths; 3 pairs of rod-shaped ams: ams1 and ams3 short, ams2 moderately long; 2 pairs of rod-shaped mes, equal in length, both placed anteromedially very close to ams. Surface of epipharynx (especially close to margin) covered with asperities. Labral rods short, rounded, slightly converging posteriorly. Mandibles (Fig. 55) curved, narrow, with divided apex (teeth different in length). There is an elongated protuberance on the cutting edge between the apex and the middle of the mandible; both mds capilliform, almost equal in length. Maxilla (Figs 56-58) with 1 stps and 2 pfs of equal length; mala with 8 finger- or rod-like dms (Fig. 57) and 4 vms, both varied in length (Fig. 58); mbs very short. Maxillary palpi with 2 palpomeres, basal with short mps; distal palpomere apically with a group of sensilla, each palpomere with a pore. Basal palpomere wider than distal, both of almost equal length. Prelabium (Fig. 56) cup-like with 1 long prms, located medially. Ligula with 2 pairs of ligs, various in length. Premental sclerite clearly visible, trident-shaped (median branch weakly sclerotized), posterior extension with elongated apex. Labial palpi 2-segmented; apex of distal palpomere with some sensilla; each palpomere with a pore. Basal palpomere slightly wider and shorter than distal. Postlabium (Fig. 56) with 3 capilliform pms, the first pair located anteromedially, the remaining 2 pairs posterolaterally; pms1 minute, pms2 very long, pms3 moderately long. Surface of postlabium and stipes partially covered with asperities.