Chelonus ( Microchelonus ) scirpophagae, Zhou & Achterberg & Tang & Chen, 2024

Chelonus ( Microchelonus) scirpophagae sp. nov.

Figs 71–72 View FIGURE 71 View FIGURE 72

Material examined. Holotype: male, Guixian County, Guangxi Prov., China, 1.X.1979, Zhihong Zhou, No. 821370 ( ZJUH). Excluded from type series: 1 male, Yuanmou Yunnan Prov., China, 1.IV.1980, Jiasheng Gan, No. 814233, reared from Scirpophaga incertulas .

Diagnosis. This new species is similar to the male of C. ( M.) clivus sp. nov. ( Fig. 21 View FIGURE 21 ), sharing the carapace with a large yellowish spot medio-basally and carapace widest after middle in dorsal view, but the two species can be separated by the following characters: apical aperture in posterior view very large, the upper corner of carapace triangularly projecting ( Fig. 72F View FIGURE 72 ) ( versus apical aperture oval and carapace without any projection dorso-apically in C. ( M.) clivus ( Fig. 22F View FIGURE 22 )); face smooth and very shiny ( Fig. 72G View FIGURE 72 , holotype) or very finely reticulate-rugulose in reared specimen ( versus transverse-longitudinally striate-rugose ( Fig. 22G View FIGURE 22 )); temples distinctly widened behind eyes ( Fig. 22H View FIGURE 22 ) ( versus narrowed ( Fig. 22H View FIGURE 22 )).

Description. Holotype, male, length of body 5.1 mm, of fore wing 3.8 mm.

Head. Head transverse, width of head 1.7 × its dorsal length; occiput hardly excavated; antenna largely missing; eye 1.6 × as long as temple in dorsal view; OOL: OD: POL=25: 11: 11; temple strongly narrowed behind eyes; frons and vertex smooth and shiny ( Fig. 72H View FIGURE 72 ); face flat, smooth and shiny, width of face 1.6 × its height; eyes slightly diverging; clypeus smooth and extending far above lower level of eyes, interspaces shiny, apical margin convex medially, clypeus 1.5 × wider than high, distance between tentorial pits 1.9 × distance between pits and eyes ( Fig. 72G View FIGURE 72 ).

Mesosoma. Length of mesosoma 1.5 × its height; side of pronotum sparsely punctate; mesopleuron completely coarsely reticulate-rugose ( Fig. 72B View FIGURE 72 ); notauli slightly impressed, mesoscutum densely alveolate-rugose; scutellum rugulose; scutellar suture comparatively deep, with short carinae; propodeum coarsely rugose, tubercles small and acute ( Fig. 72C View FIGURE 72 ).

Wings. Vein r somewhat arched; length of marginal cell 0.7 × as long as pterostigma; pterostigma length 3.6 × its width; r: 3-SR: SR1=14: 22: 66; SR1 slightly sinuate; marginal cell 1.7 × longer than submarginal cell; 1-CU1: 2-CU1= 26: 54 ( Figs 72A View FIGURE 72 ).

Legs. Hind coxa punctate; length of hind femur, tibia and basitarsus 3.1 ×, 5.4 × and 6.0 × their maximum width, respectively; length of inner hind tibial spur 0.5 × hind basitarsus.

Metasoma. Length of carapace 2.0 × its maximum width, widest after middle and apical fifth distinctly narrowed; basal half of carapace reticulate-rugose up to middle, densely punctate apically ( Fig. 72E View FIGURE 72 ); carapace in lateral view 2.8 × longer than high, posterior height of metasoma 1.8 × its anterior height, carapace apically distinctly incurved ( Fig. 72D View FIGURE 72 ); apical aperture in posterior view very large and 2.4 × wider than high, elongate, broadly slit-shaped, in lateral view wide triangular up to apical 1/4 metasoma ( Fig. 72D View FIGURE 72 ), upper corner of carapace triangularly projecting ( Fig. 72F View FIGURE 72 ).

Colour. Black; palpi brown; pterostigma and parastigma dark brown, wing and its veins dark brown, legs dark brown, but fore femur brown; metasomal carapace with yellowish band but corners black.

Female. Unknown.

Variation. Face of non-type specimen very finely reticulate-rugose and with satin sheen; frons and vertex very finely transversely rugose, occiput slightly excavated.

Biology. Solitary ovo-larval parasitoid of the rice yellow stem borer or Scirpophaga incertulas (Walker, 1863) ( Lepidoptera , Crambidae ). The biology of the reared specimen is mentioned in the publication “Identification of Natural Enemies of Rice Pests in Yunnan ” published in 1986, where this species was included as Chelonus sp. It is the first record of a Chelonus species as parasitoid of this host.

Distribution. China ( Guangxi, Yunnan).

Etymology. The name refers to the genus of its host.