Blacus ( Tarpheion ) adelphius, Lu & Chai & Achterberg & Tang & Chen, 2024

Blacus ( Tarpheion) adelphius sp. nov.

( Figs. 3–4 View FIGURE 3 View FIGURE 4 )

Material examined. Holotype: ♀, China, Liaoning, Laotudingzi National Nature Reserve , 16-19.VII.2011, Chen Huayan, No. 202029592 ( ZJUH).

Description. Female. Length of body 2.2 mm, length of fore wing 2.1 mm.

Head. Antennomeres 20; length of first flagellomere 1.4 × length of second flagellomere; length of first, second and penultimate flagellomere 5.75, 3.8 and 2.0 × their width, respectively; length of maxillary palp 1.1 × height of head; occipital carina completely absent; frontal suture shallow; OOL: diameter of posterior ocellus: POL = 17:7:8; length of eye in dorsal view 1.8 × length of temple; face smooth, densely pubescence; malar suture distinctly present, length of malar space 1.1 × basal width of mandible.

Mesosoma. Length of mesosoma 1.45 × its height; side of pronotum smooth dorsally, remainder with some striae ( Fig. 4F View FIGURE 4 ); carinae of middle lobe of mesoscutum vertical; precoxal sulcus short, only in middle of mesopleuron and shallowly crenulate ( Fig. 4F View FIGURE 4 ); notauli complete, crenulate-rugose, narrow and deep ( Fig. 4D View FIGURE 4 ); mesoscutal middle lobe truncate anteriorly; scutellum smooth, its lateral carina complete, not protruding apically; surface of propodeum smooth between carinae, its medial area widened dorsally.

Wings. Fore wing: first discal cell widely truncate anteriorly; vein r vertical ( Fig. 4G View FIGURE 4 ), length of vein r 1.0 × width of pterostigma; 1-CU1:2-CU1 = 1:8.

Legs. Hind coxa smooth ( Fig. 4I View FIGURE 4 ); length of femur, tibia and basitarsus of hind leg 5.5, 11.5 and 10.0 × their width, respectively; fore claws with some long bristles ( Fig. 4G View FIGURE 4 ), middle claws with one bristle, hind claws with one bristle.

Metasoma. Length of first tergite 2.3 × its apical width, slightly widened apically, smooth medio-basally, reticulate-rugose medio-apically ( Fig. 4E View FIGURE 4 ); remainder tergite smooth ( Fig. 4E View FIGURE 4 ); length of ovipositor sheath 0.23 × length of fore wing.

Colour. Dark brown; 4 basal antennomeres, palpi, clypeus, mandible, basally half of metasomal tergite, first and second metasomal sternites yellow; remainder of metasomal tergites and sternites, pterostigma, veins, ovipositor and its sheath yellowish-brown; tegulae yellowish-brown; parastigma whitish; bristles of fore claws blackish, one bristle of middle claws yellow, one bristle of hind claws yellow; wing membrane slightly infuscate.

Male. Unknown.

Biology. Unknown.

Distribution. China ( Liaoning).

Etymology. The specific name adelphius refers to the similarity of the new species to B. ( T.) achterbergi and is derived from “ adelphe ” (Greek for sister).

Notes. The new species is similar to B. ( T.) achterbergi Haeselbarth,1976 because occipital carina is completely absent, notauli comparatively narrow, precoxal sulcus reduced, first discal cell of fore wing widely truncate anteriorly, length of first metasomal tergite approx. 2.3 × its apical width, second metasomal tergite smooth, medial area of propodeum widened dorsally, length of vein r about equal to width of pterostigma, and 1-CU1:2-CU1 ≈ 1:8, but differs by having 20 antennomeres ( 18–19 in B. ( T.) achterbergi ), first metasomal tergite slightly widened apically and basal third largely smooth except for dorsal carinae (parallel-sided and basal third largely sculptured), head in frontal view narrowed ventrally (less narrowed), length of malar space 1.1 × basal width of mandible (distinctly less than to equal), vein 3-CU1 of fore wing strongly curved (weakly curved), hind femur widened apically (parallel-sided), and length of ovipositor sheath 0.23 × length of fore wing (0.27–0.28 ×).