Streblocera (Eutanycerus) neutra Long, 2025

Streblocera (Eutanycerus) neutra Long , sp. nov.

Figures 7 View FIGURE 7 , 8 View FIGURE 8 , 21 View FIGURE 21

Type material. Holotype, ♀, labelled “Euph. 342 ” ( IEBR), NW Vietnam: Son La, Thuan Chau, Co Ma , forest, UV light trap, 5.v.2017, PT Nhi.

Diagnosis. S. (E.) neutra , sp. nov. is relatively close to S. (E.) uncifera Li et. Al, 2020, from China, but differs from the latter by having: 1) Antenna with 26 antennomeres (vs 24 in S. uncifera ); 2) First to seventh flagellomeres with blunt serrations (vs in S. uncifera see Fig. 14D View FIGURE 14 in Li et al. 2020); 3) First tergite elongate, 2.0 × longer than its apical width (vs 1.7 × in S. uncifera ), and apical width 2.8 × longer than its minimum width (vs 3.4 × in S. uncifera ). Regarding ventral serrations of first– seventh flagellomeres, S. (E.) neutra , sp. nov. is also close to S. (E.) hsiufui You, 1993 , but differs by having: 1) Ventral serrations of first-seventh flagellomeres without hook-shaped prominence apically (vs hook-shaped prominence apically in S. hsiufui ); 2) Scapus 7.5 × longer than its maximum width (vs 8.5 × in S. hsiufui ); 3) First metasomal tergite 2.0 × (vs 2.3 × in S. hsiufui ) longer than its apical width, and 2.8 × (vs 3.1 × in S. hsiufui ) longer than its minimum width; and 4) ovipositor curved upwards (ovipositor wave-like bent in S. hsiufui ).

Description. Holotype, ♀, length of body 6.0 mm, fore wing 5.5 mm, ovipositor 0.6 mm ( Fig. 7 View FIGURE 7 ). (antenna 5.6 mm)

Head. Antenna with 26 antennomeres; length of scapus (without baso-ventral pointed horn) 7.3 × its maximum width, with tooth-shaped horn in basal 0.4 of scapus ( Fig. 8F View FIGURE 8 ); scapus 2.5 × of head height; first flagellomere 2.0 × second flagellomere; second-seventh flagellomeres serrate ventrally ( Fig. 8G View FIGURE 8 ); length from eighth flagellomere to apex of antenna subequal to scapus; in dorsal view, occipital carina nearly complete medio-dorsally ( Fig. 8A View FIGURE 8 ), width of head 1.6 × its median length, and 1.4 × width of mesoscutum (without tegulae); temple roundly narrowed behind eye; length of eye 1.5 × as long as temple; ocelli small, POL: OD: OOL= 5: 4: 14 ( Fig. 8A View FIGURE 8 ); eye 1.5 × as high as broad; in lateral view, transverse diameter of eye 1.9 × temple; in frontal view, head obliquely narrowed below ( Fig. 8B View FIGURE 8 ); diameter of antennal socket 4.5 × distance between sockets, face width as long as length of face and clypeus combined, and 1.3 × height of eye; clypeus margin straight; malar space 0.8 × as long as basal width of mandible, and 0.25 × as long as eye height; distance between tentorial pits 1.5 × distance from pit to eye margin; face in upper part with median smooth groove between antennal sockets, densely setose in lower part; clypeus with dense setae ( Fig. 8B View FIGURE 8 ); frons flat, with dense striate rugosities direct to antennal sockets; temple and vertex polished, with sparse fine punctures ( Fig. 8A View FIGURE 8 ).

Mesosoma. In lateral view, length of mesosoma 1.6 × as long as its height in lateral view; notauli narrowed anteriorly, sparsely crenulated, widened posteriorly with median carina in rugose area ( Fig. 8D View FIGURE 8 ); prescutellar sulcus wide and deep, 0.8 × as long as scutellum, scutellum smooth; median lobe of mesoscutum coriaceous; lateral lobes smooth; subalar depression rugose; pronotal side sparsely crenulated medially, smooth dorsally and ventrally ( Fig. 8E View FIGURE 8 ); precoxal sulcus long and wide, crenulated; mesopleuron smooth; metapleuron transversely rugose; propodeum with short basal carina-like rugosity, transversely rugose medio-posteriorly ( Fig. 8C View FIGURE 8 ).

Wings. Length of pterostigma 3.50 × its width, 1.25 × vein 1-R1 ( Fig. 8I View FIGURE 8 ); vein r arising distinctly behind middle of pterostigma, 0.5 × as long as width of pterostigma, and 0.2 × vein 1-R1; r: 2-SR = 5: 25; vein cu-a postfurcal; vein cu-a: 1-CU1: 2-CU1 = 6: 4: 24 ( Fig. 8I View FIGURE 8 ); hind wing: 1-M: 1r-m: 2-SC+R = 8: 11: 15.

Legs. Length of hind femur, tibia and basitarsus 9.0, 17.5 and 14.0 × as long as their maximum width, respectively; hind basitarsus 0.4 × hind tibia; hind basitarsus 0.5 × hind tibia combined, and subequal to second–fifth tarsus; fourth hind tarsus 0.7 × as long as fifth tarsus (without pretarsus).

Metasoma. Length of first tergite 2.0 × its apical width, apical width of first tergite 2.9 × its minimum width; ovipositor sheath 0.1 × length fore wing, and 0.5 × length first tergite; ovipositor flat, weakly sinuate; first metasomal tergite smooth in basal half, with oval striae medially and convergent striae apically ( Fig. 8H View FIGURE 8 ); the remainder highly smooth.

Colour. Head and mesosoma yellow; eyes silver-grey; legs and metasoma pale yellow, except first metasomal tergite yellowish brown; ovipositor sheath; pterostigma pale brown, yellow basally; wing veins yellow; wing membrane hyaline ( Fig. 8H View FIGURE 8 ).

Male. Unknown.

Host: Unknown.

Etymology. “ neuter ”, Latin meaning neither one nor the other.

Distribution. NW Vietnam: Son La province ( Fig. 21 View FIGURE 21 ).