Siobla annulicornis, Niu, Gengyun & Wei, Meicai, 2010

Niu, Gengyun & Wei, Meicai, 2010, Revision of the Siobla annulicornis, acutiscutella and sheni groups (Hymenoptera: Tenthredinidae), Zootaxa 2643, pp. 45-65 : 51-53

Siobla annulicornis sp. nov.

(Plate. 3)

Description. Holotype: Ψ.

Body length 13 mm. Body black, 4th to7th antennomeres, 2nd and 3rd abdominal tergites entirely, 4th abdominal tergite except narrow posterior margin, 2nd to 4th abdominal sternites, cerci, yellow brown; apex of sheath brown. Legs pale yellowish brown, all coxae, fore and middle trochanters largely, apical 4/7 of hind femur black, central part of middle femur dorsally with faint black macula. Body hairs pale brown. Wings yellowish hyaline, weakly but distinctly infuscate at apex, stigma yellowish brown, most of vein C and other veins dark brown (Figs. 3a, b).

Clypeus evenly punctured, interspaces narrow, distinctly shiny; head above antennal sockets, posterior orbit densely and coarsely punctured, without shiny interspaces, matt, punctures small; malar space microsculptured; dorsum of pronotum, lateral sides and posterior corner of prescutum, inner margin of scutum, mesoscutellum entirely, elevated part of mesepisternum densely and coarsely punctured, without shiny interspaces, punctures small; anterior collar of pronotum sparsely punctured, shiny; middle of prescutum, most of scutum densely punctured, with linear shiny interspaces; appendage of mesoscutellum, anterior carina of metascutellum basin, anterior margin of mesepimeron, and most of metepimeron shiny, almost impunctate; metapostnotum microsculptured, anterior and ventral part of mesepisternum sparsely punctured, shiny; basal four abdominal tergites without punctures or microsculpture, other tergites with shallow and sparse punctures and fine microsculpture.

Anterior margin of clypeus almost truncate, slightly incised at middle; malar space as long as radius of ocellus; inner margins of eyes distinctly convergent, shortest distance between eyes as long as eye height; middle fovea large and shallow, lateral fovea small and deep; supra-antennal tubercles low and obtuse, slightly elevated; frontal walls very low, indistinct; interocellar furrow distinct, bifurcate near middle ocellus, slightly deeper than postocellar furrow; postocellar area slightly elevated, wider than long as 15: 11, posterior part as high as top of ocelli, with fine middle longitudinal carina; lateral furrows curved, deep, strongly divergent posteriorly; head behind eyes shorter than eyes in dorsal view (23: 32), lateral sides curved, distinctly convergent posteriorly; occipital carina sharp, complete (Fig. 3e). Antenna with pedicel longer than broad as 3: 2, relative length of third to fifth antennomeres as 26: 15: 13, fifth to eighth antennomeres slightly dilated, compressed, inner and outer sides with shallow middle furrows. Mesepisternum angularly elevated, with indistinct corner; mesoscutellum elevated roundly, as high as top of scutum, without carina (Fig. 3g); appendage flat, anterior margin distinctly elevated at middle. Inner tibial spur of hind leg slightly shorter than half length of metabasitarsomere. Hairs on temple and mesoscutellum as long as diameter of ocellus. Ovipositor 1.5 times as long as metabasitarsomere, sheath in lateral view distinctly longer than basal plate (10: 7), ventral margin straight, apex obliquely truncate, lower corner distinctly angulated (Fig. 3h). Lancet distinctly broadened just before apex, with 14 serrulae, middle serrulae each with 1 inner and 7–8 outer subbasal teeth; middle scleroras each about 5 times as long as broad, dorsal margin of sclerora flat, almost straight (Figs. 3i, j, k).

PLATE 3. Siobla annulicornis sp. nov. (a). Female adult in dorsal view; (b). Female adult in lateral view; (c). Male adult in dorsal view; (d). Male adult in lateral view; (e). Head of female in dorsal view; (f). Head of male in dorsal view; (g). Mesonotum in lateral view; (h). Sheath in lateral view; (i). Lancet; (j). Middle serrulae; (k). Apical serrulae; (l). Harpe and parapenis; (m). Penis valve.

Male: Body length 10.5 mm (Figs. 3c, d). Colour similar to female except apex of 3rd antennomere ventrally yellow brown, outer sides of fore and middle femora basally, apical ring of hind tibia black, lateral sides of 3rd and 4th abdominal tergites black, 5th abdominal sternite yellow white; 3rd to 10th abdominal tergites with distinct, sparse punctures; malar space linear, shortest distance between eyes shorter than eye height as 4:5, head behind eyes distinctly shorter than eyes in dorsal view as 5: 9 (Fig. 3f); hairs on temple slightly longer than diameter of ocellus, apices curved; anterior margin of subgenital plate round; genitalia as in Figs. 1l and 1m.

Variability: No variability is found in the five type specimens.

Etymology: The specific epithet refers to the yellow brown middle antennomeres.

Specimen examined: Holotype: Ψ, Mt. Zhongnan, Shaanxi (33°59.506´N, 108°58.356´E), alt. 1555 m, 27 May, 2006, YANG Qin leg.; Paratypes: 4ɗɗ, same data as for holotype.

Distribution: China (Shaanxi).

Remarks: See the above key for the differences between S. annulicornis and S. leucocincta .