Sirex juvencus ( Linnaeus, 1758 )

3.3.4. Sirex juvencus ( Linnaeus, 1758)

Figure 14 View Figure 14

Ichneumon Juvencus [sic!] Linnaeus, 1758 ; Systema Naturae (1): 560. (original description)

Sirex juvencus ab. pallescens Linnaeus : Stroganova, 1973, Novye i maloizvestnye vidy fauny Sibiri (6): 73–75 (Not available. Infrasubspecific name.)

Sirex juvencus ab. ermakianum Linnaeus : Stroganova, 1973, Novye i maloizvestnye vidy fauny Sibiri (6): 73–75 (Not available. Infrasubspecific name.)

Sirex juvencus ab. noctiliolum Linnaeus : Stroganova, 1973, Novye i maloizvestnye vidy fauny Sibiri (6): 73–75 (Not available. Infrasubspecific name.)

Sirex juvencus forma tipica Linnaeus : Stroganova, 1973, Novye i maloizvestnye vidy fauny Sibiri (6): 73–75 (Not available. Infrasubspecific name.)

Material examined.

5 ♀ 10 ♂ Kadelate Village , Fuyun Country, Altai, Xinjiang, 2024-VII-28 ~ 30, Ren L leg. ; 24 ♀ Tiereketi Village , Habahe County, Xinjiang, 2017-VIII-5, 1035 m, Gao T and Lu ZB leg. ; 13 ♀ Jiadengyu National Forest Park , Altai, Xinjiang, 2017-VII-27, 1418 m, Gao T and Lu ZB leg.

Diagnosis.

Females with apical half of forewings tinted pale brownish (Fig. 14 A View Figure 14 ); vein 3 A of forewings absent; antennae with flagellar basally bright yellowish (Fig. 3 G View Figure 3 ); legs largely bright yellowish (except coxae blackish); tarsal pad of metatarsomere 2 about 0.7 times as long as ventral length of tarsomere (Fig. 7 D View Figure 7 ). Male antennae with flagellar basally bright yellowish (Fig. 3 H View Figure 3 ); hind femora bright yellowish.

Female Description.

Color: Head, thorax, coxae and abdomen black with dark blue metallic reflections (abdomen with segments II – VIII dark purple metallic reflections) (Fig. 14 A View Figure 14 ). Antennae with basal half yellowish (except for scape dark brownish to brownish) while gradient to blackish towards the apical half (Fig. 3 G View Figure 3 ). Femora brownish; tibiae and tarsi yellowish (sometimes with tarsomeres 5 brownish). Forewings with basal half clear and tinted pale brownish on apical half, brownish spot around cell 1 R 1 weakly developed. — Head: Genae with pits 0.1–5.0 pit diameters apart (Fig. 6 G View Figure 6 ); vertex with pits less than 3.0 pit diameters apart, and each pit diameter 0.11–0.32 times as lateral ocelli (Fig. 5 G View Figure 5 ). — Thorax: Mesoscutum with coarse, net-like pits in median area, transverse or longitudinal ridge indistinct or absent. Metatarsomere 2 in lateral view 2.0–2.5 times as long as height, length about 1.1–1.3 times length of tarsomeres 3 + 4; tarsal pad about 0.7 times as long as ventral length of tarsomere (Fig. 7 D View Figure 7 ). Forewings vein 3 A absent. — Abdomen: Median basin of tergum IX with basal width 0.8–0.9 times as long as median length, maximum width 1.0–1.2 times as long as median length, median length 0.7–0.8 times of cornus length. Cornus in dorsal view long and thick, with edges straight and curved apically, clearly angled at about 1 / 6 of the basal junction, its median length 1.2–1.3 as long as maximum width of abdomen at junction of terga IX and X. Sheath. Basal section 1.0–1.1 times as long as apical section. Ovipositor. Pits near middle annuli (the area at base of apical section of sheath) 0.25–0.30 times as long as an annulus, pits not decreasing in size toward base (Fig. 10 D View Figure 10 ), 0.4–0.5 times as high as lancet height in lateral view, 0.9–1.0 times as long as pits height.

Male Description.

Color: Head, thorax and coxae black with dark blue metallic reflections (Fig. 14 C View Figure 14 ). Antennae with basal half bright yellowish while blackish in the apical half (Fig. 3 H View Figure 3 ). Fore and mid legs bright yellowish from femora to tarsi. Hind legs mostly blackish except femora bright yellowish. Forewings tinted light yellow and slightly pale brownish near outer margin. Abdomen with segments I – II blackish with dark blue metallic reflections; segments V – VIII light yellowish; segments III – IV and IX largely yellowish with more or less darkish tone (Fig. 9 H View Figure 9 ). — Thorax: Metatibia about 3.9–4.0 times as long as maximum width (Fig. 8 D View Figure 8 ). Metatarsomere 1 in lateral view 3.5 times as long as maximum height.

Distribution.

Heilongjiang; Jilin; Inner Mongolia; Shanxi; Gansu; Qinghai; Xinjiang.

Host.

Picea sp. (e. g. P. crassifolia Kom. ; P. obovata Ledeb. ; P. schrenkiana Fisch. & C. A. Mey. ), P. sylvestris var. mongholica Litv.

Note.

This species is widespread in northern China. Its females can be easily identified by the yellowish color in the basal half of antennae.