Rheumatogonus intermedius Hungerford

Rheumatogonus intermedius Hungerford

Fig. 39

Rheumatogonus intermedius Hungerford 1933: Misc. Zool. Sumatrana 3–4.

Diagnosis. Males of R. intermedius can be distinguished by semicircular parameres with a pronounced basal tooth (Fig. 39), whereas R. vietnamensis has parameres with a longer parallel-sided shaft and negligible basal tooth (Fig. 38). Features of females are unreliable as diagnostic characters and are given here only as generality: Females of R. intermedius have the mesothorax with a less distinct and shorter dark hair patch and shorter body length of 5.55–5.60 mm, whereas R. vietnamensis has a more distinct and longer dark hair patch and body length of 5.65–6.40 mm (Chen & Nieser 2002).

Discussion. Rheumatogonus intermedius was described from Sumatra (Hungerford 1933) and also has been recorded from Malaysia, Thailand, and Vietnam (Cheng & Fernando 1969, Chen & Nieser 2002). In Thailand, this species has been collected in Songkhla Province (Chen & Nieser 2002). Although Vitheepradit (2000) reported the collection of this species from Loei, Phitsanulok, and Sakon Nakhon provinces based on determinations by J. T. Polhemus, those records are not valid because the specimens upon which they are based appear to be R. vietnamensis after closer examination. In this study, this species was collected from Chumphon, Kanchanaburi, Prachuap Khiri Khan, and Ratchaburi provinces. This species typically is found in slow reaches of montane streams in forested areas in Thailand. Although the winged form was rarely collected in the Malay Peninsula (Cheng & Fernando 1969), numerous winged males and females of this species were collected in this study. In Kanchanaburi, winged specimens were collected from pan black light traps.

Material examined. THAILAND: Chumphon Province: Amphur Tha Sae, Ban Meung Thong, 10°50’N 99°11’E, 98 m, 19-V-2003, Vitheepradit and Ferro, L-546 (4 males, 5 females); Amphur Tha Sae, Tumbon Ban Fon Tok, 10°46’N 99°03’E, 73 m, 24-IV-2002, Vitheepradit and Kirawanich, L-366 (7 males, 1 female). Kanchanaburi Province: Amphur Sai Yok, Mae Nam Luok, 14º26.631'N 98º48.019'E, 78 m, 24-XI-2010, KU team, C-3 (15 males, 10 females); Heuy Clity, 14º57.717'N 98º54.552'E, 674 m, 26-XI-2010, C-10 (2 males, 1 female); same locality, 22-I-2013, KU team, C-256 (1 male, 6 females); Amphur Thong Pha Phum, Heuy Ou Long, 14º46.934'N 98º40.195'E, 114 m, 2-XII-2010, KU team, C-12 (1 female); Chaloem Rattanakosin NP, pan light trap near stream Tarnngen-Tarntong Waterfall, 14º39.707'N 99º18.355'E, 326 m, 5-VIII-2011, KU team, C-65 (1 female); Prachuap Khiri Khan Province: Amphur Hua Hin, Tambon Heuy Pheung, Ban Sak Yai, stream, 12º30'N 99º34'E, 121 m, 21- IV-2012, Vitheepradit and Kirawanich, L-358 (4 males, 4 females); Amphur Kui Buri Forest Plantation Station, gravel & rock stream, 12º40'N 99º43'E, 147 m, 22- IV-2002, Vitheepradit and Kirawanich, L-360 (1 male, 1 female); Amphur Kui Buri, Forest Plantation Station, 12º04'N 99º37'E, 117 m, 17-V-2002, Vitheepradit and Ferro, L-540 (1 male, 2 females); Amphur Hua Hin, Tambon Heuy Pheung, Ban Sad Yai, 12º29'N 99º34'E, 114 m, 16-V- 2003, Vitheepradit and Ferro, L-537 (9 males, 6 females); Amphur Bang Saphan, stream from Kha On WF, 11º26'N 99º26'E, 117 m, 18-V-2003, Vitheepradit and Ferro, L-544 (1 male, 1 female); Ratchaburi Province: Amphur Suan Phueng, 49.5 km W of Amphur Chom Bueng on Hwy 3087, 13º34'N 99º15'E, 195 m, 16-IV-2002, Vitheepradit and Kirawanich, L-347 (1 male, 3 females); Amphur Pak Tho, Tumbon Yang Hak, unnamed creek, 200 m, 13º19'N 99º33'E, 200 m, 18-IV-2002, Vitheepradit and Kirawanich, L-353 (4 males, 4 females); Amphur Saun Pheung, Heuy Kog Moo, 13º27.786'N 99º15.210'E, 198 m, 13-XII-2012, KU team, C-88 (4 males, 2 females).