Aglaostigma niuae, Liu & Li & Wei, 2025

Liu, Meng-Meng, Li, Ze-Jian & Wei, Mei-Cai, 2025, Review of the Aglaostigma niuae group (Hymenoptera: Tenthredinidae) with descriptions of four new Chinese species, European Journal of Taxonomy 981, pp. 38-51 : 39-40

Aglaostigma niuae species group

Diagnosis

Body thin and long; in females, body mostly reddish brown, partly black, yellow or yellowish white; in males, body mostly black, partly yellowish white or reddish brown; antennae slender, with several segments ranging from yellowish white to reddish brown, conspicuously longer than head and thorax combined, usually slightly longer than abdomen; mesoscutellum yellow (partly yellowish white in male); abdominal terga 2–6 laterally yellowish white; clypeus almost truncate; postocellar area usually narrow and long, 2–4 × broader than long; metatarsomere 1 not shorter than following 3 tarsomeres combined; valvula 3 not shorter than valvifer 2; lancet narrow and long, with 11–14 serrulae, denticles clear and usually large.

Morphologically, the A. niuae group and the A. malaisei group are similar. However, compared to the A. niuae group, the A. malaisei group is characterized by the more body robust, thicker but not slender antennae that are nearly as long as the abdomen, the malar space as broad as the diameter of median ocellus, and the postocellar area is usually twice as broad as long.

Key to species of the Aglaostigma niuae group from China

1. Posterior corner of metepimeron yellow; middle fovea of head deep and large .............................. 2

– Metepimeron reddish brown or blackish brown; middle fovea of head shallow and small ............. 3

2. Female: antennomeres 1–4 reddish brown, antennomeres 5–6 yellowish white, antennomeres 7–9 black; head and thorax largely reddish brown, partly with black, yellow or yellowish white maculae; abdominal terga 1–6 (or 8) laterally with broader yellowish white stripe; hind tibia and metatarsomere 1 entirely reddish brown. China (Hubei, Shaanxi) .................................... A. tricoloricorne sp. nov.

– Male: antennal scape, pedicel and dorsal side of flagellum blackish brown, ventral side of flagellum reddish brown; head and thorax largely black, partly with yellowish white maculae, without reddish brown macula; abdominal terga 1–6 laterally with narrower yellowish white stripe; most parts of hind tibia and metatarsomere 1 reddish brown, small parts blackish brown. China (Zhejiang) ........ .......................................................................................................................... A. hejunhuai sp. nov.

3. Postocellar area 4 × broader than long; apex of antennomere 5, antennomere 6 yellowish white; metatarsomere 1 mostly light reddish brown, tarsomeres 2–4 yellowish white; pronotum partly reddish brown, posterior yellow; tegula yellowish white to reddish brown; forewings with cross-vein cu-a joining cell 1M at basal 0.3, vein 2r joining cell 2Rs at middle 0.5; middle serrulae of lancet with 6–7 distal denticles, cypsella short. China (Tibet) ............................... A. niuae sp. nov.

– Postocellar area 3 × broader than long; antennomeres 5–6 entirely yellowish white; pronotum, tegula entirely reddish brown; forewings with cross-vein cu-a joining cell 1M at basal 0.4, vein 2r joining cell 2Rs at apical 0.4; middle serrulae of lancet with 3–5 distal denticles, cypsella rather long. China (Sichuan) .................................................................................................... A. leucotarsalina sp. nov.