Gymnetron miyoshii Miyoshi, 1922

Jiang, Chunyan & Zhang, Runzhi, 2015, The genus Gymnetron from China with description of pre-imaginal stages of G. miyoshii, G. auliense and G. vittipenne (Coleoptera, Curculionidae), ZooKeys 534, pp. 61-84 : 62-67

Taxon classification Animalia Coleoptera Curculionidae

Gymnetron miyoshii Miyoshi, 1922

Gymnetron miyoshii Miyoshi, 1922: 253

Gymnetron villosulum var. orientale Voss, 1955: 139

Description.

Adult (Figures 1-2): sides of pronotum in part, mesothoracic epimera, metasternum and urosternite one covered with broad scales; elytral vestiture forming indistinct spots; rostrum in lateral view slightly curved, in female nearly of same width from base to apex ( Caldara 2008).

Egg: oval, yellowish, nearly pellucid. Measurements (mm): diameter: 0.11-0.12 (n = 3), length: 0.28 (n = 3).

Mature larva (Figure 9): Measurements (mm): body length: 3.25-3.90 (n = 2), width: 1.08-1.30 (n = 2); capsule length (in front view): 0.48-0.50 (n = 4), width: 0.38-0.43 (n = 4); body slender and weakly curved, yellowish, subcylindrical, widest at thorax in lateral view, attenuate posteriorly; head brown with pale stripes at sides and along ecdysial line; cuticle minutely spiculate; pronotum partly pigmented and sclerotized; body segments with minute setae, pedal lobes in conspicuous pigmented knobs.

Head (Figures 10-11): free, circular in outline, broader than long, broadest at middle; cranial suture undivided, wide, half length of head; frontal suture distinct, not extending to mandibular membrane; endocarinal line short, no more than half as long as frons; frons with three pairs of fs, fs1 and fs3 reduced to basal sensilla, fs5 longest, laterally positioned on epistoma close to antenna, fs4 located near epistoma, half as long as fs5, fs2 located in the middle of frons, half as long as fs4; dorsal epicranium with four pairs of des, des4 reduced to a basal sensillum, des3 longest, located on frontal line, des5 lightly shorter than des3, des2 approximately one quarter as long as des3, des1 slightly shorter than des2; epicranium with two pairs of les, les1 long, les2 short, about half as long as les1; posterior epicranium with three pairs of pes, pes1 minute, pes2 equally as long as pes3; ventral epicranium with one pair of ves, minute; postoccipital condyles indistinct, hypopharyngeal bracon distinct; tentorial bridge narrow, with two small but moderately acute anterior projections and two large, obtuse-angled posterior projections; clypeus transverse, fused to labrum, bearing two pairs of cls, cls1 nearly same length as cls2, located in one line, parallel to clypeus, sensilla absent; antenna (Figure 12) one segment, sensory appendage nearly twice as long as wide, circular in cross-section, contiguous with frontal suture, with one conical and three minute sensilla; ocellus present, not projecting, located below stripe at side, externally close to antenna.

Mouthparts (Figures 13-17): mandibles (Figure 13) symmetric, incisor section with two apical teeth and rounded flange posterior to dorsal tooth, molar section with two mds, mds1 nearly same length as mds2, sensilla distinct; labrum (Figure 14) transverse, fused to clypeus, nearly completely sclerotized, with three pairs of lrms, lrms2 slightly shorter than lrms1, both centrally localized, lrms3 same as lrms1, close to distal margin of labrum; epipharynx (Figure 15) with all epipharyngeal setae stout and apically rounded, with two pairs of als, three pairs of ams, epipharyngeal sensilla, mes and labral rods (tormae) absent. Labium (Figure 16) membranous excepting the premental sclerite, labial palpus with one segment, slightly longer than wide, apex of palpus flattened with dense short irregular spiculate setae, and one sensillum; premental sclerite (Pmsc) distinctly posteriorly and laterally dilated, U-shaped, with one pair of sensilla and one pair of long prms. Ligula with two pairs of tiny ligs, ligs1 as long as ligs2. Postlabium (plb) partly sclerotized, with two pairs of plbs at membranous area, plbs1 long, plbs2 short, one quarter long as plbs1; membranous area sparsely and finely asperate. Maxillae with maxillary palpus (mxp) (Figures 16-17) two-segmented, basal segment with one tiny mxps, accessory appendage absent; distal segment sclerotized, apex flattened with dense short irregular spiculate setae, one sensillum; mala with five dorsal robust dms, dms1-5 gradually shorter, with four shorter, more acute vms. Stipes bearing one stps, two pfs and two sensilla, stps strong and long, submedian on venter of base. Pfs1 a little shorter, located near mala, one third as long as pfs2, pfs2 submedian on venter of base, cardo completely divided from stipes.

Thorax (Figure 9): pronotal shield partly pigmented and sclerotized on pale smooth plate. Pronotum with two setae on sclerotized area, dorsopleurum with four dpls; spiracle (Figure 18) intersegmental between pro- and mesothorax, bicameral, air-tube subequal to diameter of circular peritreme; ventropleurum with two vpls; pedal area (Figure 19) distinct, pedal lobe present, one-segmented, slightly convex, with four setae; mediosternum with two msts. Mesonotum with two folds (prodorsum and postdorsum), prodorsum with two prs, postdorsum with two pds, two setae transversally aligned; alar area with four as, two long, two short; dorsopleurum with one dpls, ventropleurum with one vpls; setae of pedal area and mediosternum same as prothoracic. Metanotum same as mesonotum.

Abdomen (Figure 9): with spiracles on segments I-VII, size similar, all anterolateral and unicameral, each with single annulated air-tube, pointing posteriad, subequal to diameter of circular peritreme. Abdominal segments I-VII with tergites with two folds, prodorsum with two prs, prs1 longer than prs2, postdorsum with soft protuberance posteriorly, with one pds, all setae shorter than thoracic setae; spiracular area with two ss, ss1 short, one quarter as long as ss2; dorsopleurum with one dpls, ventropleurum with one vpls, laterosternum with one lsts, mediosternum with three msts, except msts3 in front of msts1, other five setae short and transversally aligned. Abdominal segment VIII with tergite with two folds, prodorsum with one prs, postdorsum with one pds; spiracular area with two ss, ss1 short, one quarter as long as ss2; dorsopleurum with one dpls, ventropleurum with one vpls, laterosternum with one lsts, mediosternum with one msts, except msts2 in front of msts1, other four setae short and transversally aligned. Abdominal segment IX with tergite with two folds, prodorsum with one prs, postdorsum with one pds; pleurum with one pls, sternum with three sts. Abdominal segment X with one tiny seta, anus transverse cleft.

Pupa (Figures 20-22): Measurements (mm): length: 2.65-3.00 (n = 4), width: 1.00-1.60 (n = 4), height: 1.25-1.50 (n = 4). General appearance: Theca yellow, grayish at apex of antennae, rostrum, legs, wings, elytra, anus and apex and base of ventrites. Setae greatly reduced in number. Ventrites III-X visible in ventral view, tergum I-VIII visible in dorsal view. Head: yellow-gray with one yellow stripe along middle, with one pair of pas, situated at middle margin of eyes; eyes large, one third of length of head, not projecting; rostrum long, twice as long as wide, mesorostrum visibly dilated, mandibular theca weakly projecting, setae absent; antennae applied against prosternum and apically extending to propleurum, subparallel to profemur. Thorax: prothorax bearing one median, lightly pigmented tubercle, apically shallowly bifurcate, with a spiracle between pronotum and mesonotum, but lacking air-tube; pronotum with one as and one sls in ventral view, two pls in dorsal view, as, sls and pls subequal, strong and long, pls1 and pls 2 positioned in one transversal row; mesonotum with two msns on scutellum; metanotum bearing two mtns near hind margins, half shorter in length than pronotal setae. Legs: pro-, meso- and metafemora apically bearing two slightly outcurved fes, fes 1 as long as fes 2, apex with grey circular pigmented area. Abdomen: segments I-VII with tergite bearing one seta, with transversely oval impression, submedian small transverse macula and lateral maculae, segment VII lacking impression. Spiracles present on segments I-VII, spiracular area with one ss, dorsopleurum with one dpls, ventropleurum with one vpls, laterosternum with one lsts, mediosternum with two msts; segment VIII with tergite bearing one fleshy, pigmented, apically narrowing rounded process, with two seta on tergite, sternum with two setae; segment IX with sclerotized, bifurcate, elongate and slightly curved outward pseudocerci, subterminally positioned at ventral abdominal segment IX, invisible in dorsal view; segment X with anus transverse cleft, subterminal, invisible in dorsal view.

Specimen examined.

CHINA: Hunan: Food and Drug Administration of Changsha (28°11.85'N; 113°0.36'E, 43m), 18-VIII-1975, Veronica anagallis-aquatica L.(8); same except: Hunan Medical University (28°18.05'N; 112°52.14'E, 48m), VII-1979, Veronica spp.(3); Institute of Plant Protection of Hunan (28°12.01'N; 113°04.86'E, 45m), 1973, Veronica anagallis-aquatica L. (2); 1975 (6); 24-V-1976, Veronica anagallis-aquatica L., leg Yangchang Zhao (10); 21-V-1976, Veronica anagallis-aquatica L., leg Qiong Zhu (2); 16-V-1976, Veronica anagallis-aquatica L. (5). Inner Mongolia: Hohhot (40°49.28'N; 111°38.82'E, 1289m), 15-VI-1965, Veronica undulata Wall., leg Hongchang Li (5); Molidawanqi, Hulun Buir (48°28.53'N; 124°30.18'E, 335m), 23-VII-1940 (1). Hebei: Manzuxiang, Dongling, Zunhua, Tangshan, (40°10.90'N; 117°54.49'E, 120m), 8-VII-1963, Veronica spp., leg Wenzhen Ma (1). Beijing: Badaling, (40°20.49'N; 115°58.88'E, 669), 20-VI-1963, Veronica anagallis-aquatica L., leg Tiesheng Li (9); Sanpu, Yanqing (40°19.65'N; 116°02.18'E, 593m), 28-VII-1980, Veronica undulata Wall. (18); 1980-VI-29, Veronica undulata Wall., leg Shengqiao Jiang (10); 7-VII-1980, Veronica anagallis-aquatica L., leg Subai Liao (29); Beizhaicun, Qiaozizhen (40°19.77'N; 116°33.34'E, 73m), 1-VI-2013, Veronica anagallis-aquatica L., leg Chunyan Jiang (26); 24-V-2014, Veronica anagallis-aquatica L., leg Chunyan Jiang (4); 14-VI-2014, leg Chunyan Jiang (5 eggs, 13 larvae, 6 adults). Jiangsu: Yinqiao, Suyang, Changzhou (31°25.94'N; 119°29.73'E, 8m), 5-VI-1981 (1); Wujin (31°40.16'N; 119°55.93'E, 4m), 12-V-1955 (1); Hangzhou (30°15.33'N; 120°12.50'E, 6m), 1982, leg Guangsheng Li (1). Heilongjiang: Harbin (45°45.94'N; 126°38.70'E, 116m), 18-V-1945 (1).

Biological notes.

Veronica anagallis-aquatica L. has been collected with galls on 14-VI-2014 which have been reared in the laboratory. Fifteen pupae were found on 21-VI-2014.