Episyron immaculatus Song & Ma

Song, Zhiyan, Dong, Lili, Ma, Li & Li, Qiang, 2025, Review and key of the Chinese species of the genus Episyron Schiødte (Hymenoptera, Pompilidae), including descriptions of two new species, Deutsche Entomologische Zeitschrift 72 (2), pp. 133-154 : 133-154

Episyron immaculatus Song & Ma sp. nov.

Fig. 3 A – F

Material examined.

Holotype: CHINA • ♀; Inner Mongolia, Helan Mountain, Xiangchizi ; 38°49'N, 105°52'E; 7. VIII. 2010; coll. Fangzhou Ma; sweep net ( YNAU) ; Paratypes: CHINA • 1 ♀; Inner Mongolia, Helan Mountain, Xiazigou ; 39°12'N, 105°42'E; 9. VIII. 2010; coll. Fangzhou Ma; sweep net ( YNAU) ; CHINA • 1 ♀; Inner Mongolia, Helan Mountain National Nature Reserve ; 38°21'N, 105°44'E; 26. VII. 2010; coll. Dingji Zhang, sweep net ( YNAU) .

Description.

Female. Length: body 10.5–12.5 mm; fore wing 8.1–9.8 mm.

Colour. Body black, yellow marks as follows: narrow stripes along inner orbit in median part of face in frontal view, stripes along posterior margin of eyes (Fig. 3 B, C ). Mid, hind femora (apical black) and tibiae reddish, spur brown (Fig. 3 A ). Fore wings slightly dark, with brownish apical band (Fig. 3 E ).

Pubescence. Mandible, scape, vertex, gena, pronotum, propodeum and apical metasoma with sparse black setae; pronotum, scutellum, metanotum, metapleura, metapostnotum, propodeum, dorsal surface of hind coxa and T 1 with unevenly distributed, brown squamiform pubescence (Fig. 3 A – D ).

Head. In frontal view, head width 1.17–1.20 times its height (Fig. 3 B ). Mandible slender, with two subapical teeth. Clypeus slightly convex medially, anterior margin rounded, its width 1.95–2.11 times length (Fig. 3 B ). Malar space short. Area between antennal sockets convex. Frons flat, with long and conspicuous median line, extending to anterior ocellus (Fig. 3 B ). Inner orbits nearly parallel below and slightly convergent above; MID width 1.85–1.89 times eyes; LID: MID: UID = 68: 69: 50 (Fig. 3 B ). In dorsal view, ocelli approximately in obtuse triangle, ocellar area slightly raised; POD: OOD = 1.34–1.67 (Fig. 3 C ). Head with developed occipital angles, occipital carina conspicuous (Fig. 3 C ). In lateral view, gena 0.26–0.28 times eye width. Flagellum filiform, F 1 slender, length 5.25–5.78 times its maximum width, and 1.62–1.73 times scape; SL: PL: F 1: F 2: F 3: F 4: F 5 = 31: 10: 52: 37: 33: 30: 26.

Mesosoma. Pronotum length in dorsal view 0.43–0.58 times its maximum width, slightly converging toward base, posterior margin arcuate and slightly angulate medially. Mesoscutum with evident parapsidal line, from apical to 3 / 4 metanotum (Fig. 3 A ). Mesoscutellum and metanotum conspicuously convex medially. Metapostnotum narrow medially, and posterior margin arcuately expanded, and its length nearly 0.33–0.45 times metanotum (Fig. 3 D ). Propodeum slightly convex in profile, with uniform arcuate transition, length 0.74–0.80 of its maximum width (Fig. 3 D ).

Wings. Marginal cell of fore wing nearly as long as its length from the wing tip (Fig. 3 E ). Pterostigma short, its posterior margin rounded (Fig. 3 E ). Fore wing with three submarginal cells, SMC 3 apparently greater than SMC 2 (Fig. 3 E ). SMC 2 receiving crossvein 1 m-cu at basal 0.61–0.63, SMC 3 receiving crossvein 2 m-cu at basal 0.54–0.60 (Fig. 3 E ). Hind wing crossvein cu-a arc-like, M + CuA vein fork before intersection of cu-a and M + CuA (Fig. 3 E ).

Legs. Fore tarsus with flattened spines, slightly widening or almost parallel-sided toward subapex (Fig. 3 F ). Tarsomere 1 outside with four outer spines, first spine shorter; tarsomere 2, 3 with two outer spines; tarsomere 4 with one outer spine; tarsomere 5 without spine; three spines on ventral surface of tarsomere 1; apical spine of tarsomere 1 exceeding apex of tarsomere 2; tarsomere 2 apical spine extended beyond apex of tarsomere 3, a row of small spines on ventral surface of tarsomeres 1–4 (Fig. 3 F ). Long spur of hind tibia 0.80–0.82 times of metatarsus. Tarsal claws symmetrical and bifid, inner tooth broad and obliquely truncated (Fig. 3 F ).

Metasoma. Metasoma without petiole, apex of T 6 slightly compressed (Fig. 3 A ).

Male. Unknown.

Distribution.

China: Inner Mongolia (Alashan).

Etymology.

The specific epithet immaculatus originates from the prefix “ im - ” and the Latin word “ maculatus ”, and refers to the black metasoma, without any spots or bands.

Remarks.

The new species clearly differs from Episyron rufipes ( Linnaeus, 1758) and other congeners by the following characteristics:

Female of E. immaculatus : F 1 length 5.25–5.78 times its maximum width; POD: OOD = 1.34–1.67 (Fig. 3 A ); mid, hind femora (apical black) and tibia reddish (Fig. 3 A ); pterostigma short, its posterior margin rounded (Fig. 3 E ); pronotum, mesonotum and metasoma black, without any spots or bands (Fig. 3 A, D ).

In Episyron rufipes ( Linnaeus, 1758) (female): F 1 length 5.78–6.5 times its maximum width; POD: OOD = 1.18–1.33 (Fig. 9 C ); apical 2 / 3 of mid femora, hind femora (basal black), mid and hind tibia reddish (Fig. 9 A ); pterostigma elongated, its posterior margin parallel to anterior one (Fig. 9 E ); a yellow spot on tegulae, paired basolateral roundish spots on T 2, paired basal transverse large spots on T 3 (sometimes connected), spots on T 4-5 usually hidden, and roundish light yellow spot on T 6 basally (Fig. 9 A, D ).

Figures

Figure 3. A – F. Episyron immaculatus Song & Ma, sp. nov., ♀, holotype. A. Female, dorsal view; B. Head, frontal view; C. Head, dorsal view; D. Postnotum, propodeum, dorsal view; E. Fore wing and hind wing; F. Fore tarsus. Scale bar: 1.0 mm.

Figure 9. A – F. Episyron rufipes (Linnaeus, 1758), ♀. A. Female, lateral view; B. Head, frontal view; C. Head, dorsal view; D. Postnotum, propodeum, dorsal view; E. Fore wing and hind wing; F. Fore tarsus. Scale bar: 1.0 mm.