Beldonea Cameron is an unusual genus of Tenthredininae, which, in part, is distinguished from other genera of the subfamily by the serrate antennae of the female (Fig. 1) and pectinate antennae of the male (Fig. 2). Lacourt (1996) proposed a new subfamily and new tribe of Tenthredininae, Beldoneinae and Beldoneini, for this genus, including only Beldonea and synonymizing Flagellaria Saini et al. Almost simultaneously, Wei (1997) proposed a new tribe, Beldoneini, including four genera, Beldonea, Flagellaria, Cromaphya Rohwer, and Oculocornia Wei. Lacourt’s (1996) synonymy of Beldonea and Flagellaria was followed by Saini et al. (2006), Saini (2007), and Taeger et al. (2010). However, Wei et al. (2006) chose to keep Flagellaria as a distinct genus. In different chapters in the same book, Flagellaria is treated as a valid genus (Wei et al. 2006) and as a synonym of Beldonea (Saini et al. 2006). Here, I follow Lacourt (1996), Saini et al. (2006), Saini (2007), and Taeger et al. (2010), although Wei (1997) makes some good justification for keeping Flagellaria valid, e.g., the 10-segmented, serrate antenna (Figs 1, 2), absence of antennal organs, round metepimeral appendage, and impunctate mesopleuron.

The genus and species, Beldonea impunctata (Wei), are recorded from Thailand for the first time. The presence of the genus in Thailand is not surprising since it has been recorded from Malaysia (Malay Peninsula), China (Hainan and Yunnan), and northeastern India (as Flagellaria, Wei 1997). Five species of Beldonea are listed by Taeger et al. (2010), Beldonea lubens (Konow) and Beldonea okutanii (Saini et al.) from India, Beldonea pendleburyi (Forsius) from the Malay Peninsula, and Beldonea impunctata (Wei) and Beldonea fumosa Wei from China. Females of the Thai specimens clearly key to Beldonea impunctata, described from Yunnan, in Wei’s (1997) key to the four Flagellaria species. However, the malar space used by Wei (1997: 6, couplet 2) is invalid because Beldonea okutanii has a linear malar space as do the other species, not broad as described by Saini et al. (1985).

The male of Beldonea impunctata was unknown, but the series from Thailand associates the sexes, and the male is here separated from that of Beldonea okutanii from India. Both are distinguished from Beldonea fumosa Wei by the rounded apex of the penis valve (Figs 4, 6) as opposed to the acute apex in Beldonea fumosa (Wei 1997, fig. 11). The color and antennal characters for B. impuntata and Beldonea okutanii are identical and the only notable differences are in the genitalia. The general shape of the penis valve of Beldonea impunctata (Fig. 4) is similar to that of Beldonea okutanii illustrated by Lacourt (1996, fig. 57), Saini et al. (1985, fig. 15), and Saini (2007, fig. 652), although the illustrations of these authors slightly differ. These authors do not illustrate the genital capsule. The genital capsule and penis valve of both species are compared in Figs 3–6. In Beldonea impunctata (Figs 3, 4), the inner margin of the harpe is more strongly indented, the parapenis is somewhat longer and more slender, and the penis valve has a somewhat stronger hook at its apex and longer and more slender valvura. In Beldonea okutanii (Figs 5, 6), the inner margin of the harpe is almost straight, the parapenis is somewhat shorter and stouter, and the penis valve has a less defined hook at the apex and the valvura is broadened almost to the base. The punctures on the mesoscutellum also may be of some help. In Beldonea okutanii, they are more numerous and as close or closer together than the shiny interspaces, whereas in Beldonea impunctata, the punctures are less numerous and farther apart than the shiny interspaces.

New records for Beldonea impunctata are as follows: THAILAND: Phetchabun, Khao Kho NP, deciduous forest at Ta Pol river, 16°32, 539’N, 101°2.483’E, 242 m, Malaise trap, 26.v-2.vi.2007, Sonchai Chachumnan & Saink Singtong leg, T2558 (1 ♂); Kamphaeng Phet, Mae Wong NP, Chong Yen, 16°5.968’N, 99°6.472’E, 1306 m, Malaise trap, 1–8.x.2007, Chumpol Piluk & Aram Inpuang leg, T2816 (1 ♂); Kamphaeng Phet, Mae Wong NP, Chong Yen, 16°5.212N, 99°6.576’E, 1306 m, Malaise trap, 14–21.iv.2008, Piluek C. leg, T3633 (1 ♂); Kamphaeng Phet, Mae Wong NP, Chong Yen, 16°5.968’N, 99°6.472’E, 1306 m, Malaise trap, 3–10.ix.2007, Chumpol Piluk & Aram Inpuang leg, T2812 (1 ♀, 1 ♂); Chiang Mai, Doi Phahompok NP, Headquarter, 19°57.961’N, 99°9.355’E, 569 m, Malaise trap, 18–25.vii.2007, Seesom. K. leg, T2947 (1 ♂); Chiang Mai, Doi Phahompok NP, Headquarter, 19°57.961’N, 99°9.355’E, 569 m, Malaise trap, 25.vii-1.viii.2007, Wongchai. P. leg, T2951 (1 ♂); Chiang Mai, Doi Chiangdao NP, Pha Tang substation, 19°24.978’N, 98°54.886’E, 526 m, Malaise trap, 4–11.ix.2007, S. Jugsu & A. Watwanich leg, T5682 (1 ♂); Chiang Mai, Doi Phahompok NP, Headquarter, 19°57.961’N, 99°9.355’E, 569 m, Malaise trap, 1–7.viii.2007, Wongchai, P. leg, T2949 (2 ♀). Specimens are deposited in the Queen Sirikit Botanical Garden Entomological Collection, Chiang Mai, Thailand, and the National Museum of Natural History, Washington, D.C., USA (USNM).

I have examined a female and a male of Beldonea okutanii collected from the type locality: India, Sikkim, Gangtok, 1750 m, 11-5-86, M. Saini (USNM).