Simplicia bimarginata ( Walker, 1864 )

Raha, Angshuman, Sanyal, Abesh Kumar & Singh, Navneet, 2025, On the taxonomy of genus Simplicia Guenée, with a new species from India (Lepidoptera: Erebidae: Herminiinae), Zootaxa 5631 (3), pp. 451-474 : 459

Simplicia bimarginata ( Walker, 1864)

( Figs. 1–6, 30–35, 38)

Culicula bimarginata Walker, 1864 , J. Proc. Linn. Soc. (Zool.), 7: 178. (TL: Sarawak, Borneo, Malaysia)

= Simplicia (?) infausta Felder & Rogenhofer, 1874, Reise Fregatte Novara, Bd 2 (Abth. 2) (4): pl. 120, f. 45. (TL: Sarawak, Borneo, Malaysia)

Material examined: India, Arunachal Pradesh, Changlang Dist. , Namdapha NP: 1 ♀, 29 mile (27º29'15.8"N, 96º27'30.3"E, Alt. 371 m), 31.x.2015, 1 ♂, 29 mile, 02.xi.2015, A. Majumder & Party leg ., 1 ♂, Deban FRH (27º29'53.5"N, 96º23'27.6"E), 01.iii.2017, A. Pyra & Party leg. , 1 ♂, Deban FRH, 25.vi.2017 , 1 ♂, Deban FRH, 26.vi.2017, J. Sainy & Party leg. West Bengal, Kalimpong Dist., Neora Valley NP : 2 ♂, 1 ♀ (3594), Suntaleykhola (27.0103ºN, 88.7899ºE, Alt. 761 m), 08.vii.2018, K. Bhattacharyya & Party leg. , 2 ♂, Suntaleykhola , 25.ix.2018 , 2 ♂, Suntaleykhola , 27.ix.2018, P.C. Pathania leg. Sikkim, South Sikkim , Ravangla , 1 ♀, 23.vii.2019, H. Singh leg. Andhra Pradesh, Vishakhapatnam Dist .: 1 ♂, Garudaguda (18º17'46.5"N, 82º56'37.9"E), 06.x.2021, S.K. Shah leg.

Diagnosis: Forewing length: ♂ 17–20 mm; ♀ 20–22 mm. This species is externally indistinguishable from S. griseolimbalis Snellen, 1886 ( Holloway 2008: 120, pl. 5, f. 286, 295; Kononenko & Pinratana 2013: 27, pl. 2, f. 28, 29) and S. moorei Swinhoe, 1919 ( Figs. 7, 8) ( Holloway 2008: 120; Kononenko & Pinratana 2013: 27, pl. 2, f. 30, 31) and is best separable by male genital characters. However, Holloway (1982) indicated a few external features of S. griseolimbalis differing from S. bimarginata , such as slightly larger size, darker colouration and usually more oblique and less curved ante-medial line on the forewing. But, these characters are subject to individual variations depending on the locality of occurrence. All three species have a general wing pattern more or less similar to S. schaldusalis (Walker, [1859]) ( Figs. 26, 27), but, in S. bimarginata , the black shading towards the sub-marginal line is more intense and males usually larger than females (in our collection, both the female specimens are larger), while they are smaller in S. griseolimbalis ( Holloway 2008) . In the male genitalia, S. bimarginata ( Figs. 30–35) differs from S. griseolimbalis by broader and distinctly domed uncus, presence of a curved spine at the subapical region of valva costa (in S. griseolimbalis , the costal spine is situated apically), roundish rather than quadrate valva apex, and shorter and slightly arcuate aedeagus. With S. moorei ( Figs. 36, 37), the delineation of S. bimarginata is narrow and can be found in aedeagus vesica which has tuberose signa restricted to the dorsal surface rather than uniformly spread as seen in S. moorei . Moreover, the aedeagus in S. moorei is more curved than that in S. bimarginata . Although such minor differences between these two species are indicative of the subspecific variations of a single species, their sympatric occurrences in Singapore and the Eastern Ghats region of India may suggest their identity as separate species ( Holloway 1982).

Distribution: India: Andhra Pradesh, Arunachal Pradesh, Assam, Kerala, Maharashtra, Mizoram, Jharkhand, Sikkim, Tamil Nadu, West Bengal, ( Kirti et al. 2017, Singh 2019, Chandra et al. 2019). Global: Indonesia (Sulawesi, Sumatra), Malaysia (Borneo), Papua New Guinea, Philippines, Singapore, Sri Lanka, Taiwan, Thailand ( Holloway 1982, 2008; Lödl 1999; Kononenko & Pinratana 2005).

Remark: In the present study, apart from differences in the overall size, individual variations in the size of uncus and position of the costal spine of valva in male genitalia of S. bimarginata are observed ( Figs. 32, 34). Whether these differences are actually species level variations or not, can only be resolved through molecular studies. This species occurs in the lowland to mid-altitude moist-deciduous forested habitats up to about 1200 m elevation. Holloway (2008) mentioned the likely occurrence of both S. bimarginata and S. griseolimbalis in the forested as well as disturbed habitats up to 2000 m altitude, although the former being relatively uncommon.