Asiobaccha nubilipennis (Austen, 1893) comb. nov.

(Figures 8a, b, e, 12c, 13a, b, 14a)

Baccha nubilipennis Austen, 1893: 136. Lectotype: ♂, BMNH, here designated. Type locality: Sri Lanka: Kandy. Wulp 1896: 121; Brunetti 1910: 171; Kertész 1910: 157; Kertész 1913: 275; Brunetti 1915: 218; Sack 1922: 261; Brunetti 1923: 116, 413; Curran 1928: 247; Shiraki 1930: 414, 416; Sack 1932a: 216, 218; Cherian 1934: 698; Keiser 1958: 190, 201; Biswas et al. 1975: 24; Ahmad and Nasim 2009: 353.

Baccha nubilipennis Matsumura 1916: 225.

Baccha (Asiobaccha) nubilipennis of Violovitsh 1976: 131, 132.

Baccha (Allobaccha) nubilipennis of Knutson et al. 1975: 322; Kapoor et al. 1979: 60; Thapa 2000: 326; Mitra et al. 2008: 13.

Allobaccha nubilipennis of Muraleedharan and Radhakrishnan 1986: 307; Peck 1988: 53; Radhakrishnan and Muraleedharan 1993:176, 177; Cheng and Huang 1997: 424; Cheng and Huang 1998: 120; Hazarika et al. 2001: 167; Dirickx 2010: 231; Huang and Cheng 2012: 72.

Asiobaccha nubilipennis of Ghorpadé 1994: 4.

Episyrphus (Asiobaccha) nubilipennis of Thompson and Rotheray 1998: 97, fig. 5.76; Rojo et al. 2003: 56; Mengual et al. 2008: 545; Ichige 2009: 10 – 12.

Differential diagnosis

This taxon has a broad alula, mostly bare, with a yellow face and a pale scutellum (Figures 8e, 14a), with a well-defined mesonotal collar, and the metatarsus bicolourous (Figure 8a). This species has an infuscated wing, bare basomedially (including basal part of cell R), and terga 1 and 4 black (Figures 8a, 12c, 14a), characteristics that differentiate A. nubilipennis from A. virtuosa. Asiobaccha nubilipennis belongs to a species group with mesonotal fringe, which includes A. aea, A. virtuosa, A. doesburgi, A. notofasciata, A. aquila and A. bimaculata. Morphologically, the most similar species to A. nubilipennis is A. bimaculata, also with terga 1 and 4 black and metatarsus bicolourous, but they can be identified using the characteristics in the key. Moreover, A. nubilipennis has tergum 3 black with a basomedial yellow fascia not reaching basal margin, a different abdominal pattern from A. bimaculata that has tergum 3 with two medial subtriangular yellow maculae pointing anteriorly.

Variation. Species slightly variable, although its geographical distribution is the largest in this genus. Some specimens of A. nubilipennis from Sumatra have the cell R almost entirely microtrichose but with a basal, small bare area. The infuscation of the wing is very variable, from a medial, small brown area to a complete dark brown wing. The author has studied a female (JAPAN: Ryukyu, Iriomote Island, 1 July 1932; USNM) that has the yellow fascia on abdominal tergum 3 divided medially into two maculae.

Length (N = 5). Body, 11.6 – 17.0 (14.0) mm; wing, 10.0 – 14.0 (12.0) mm.

Biology

Muraleedharan and Radhakrishnan (1986) and Radhakrishnan and Muraleedharan (1993) reported larvae of A. nubilipennis feeding on Aphis (Toxoptera) aurantii in tea plantations in Anamallai Hills, Tamil Nadu, India.

Geographical distribution

Species with the widest geographical range in the genus. It is known from Sri Lanka, India, and Nepal * through China * to Japan, Myanmar *, Taiwan, Vietnam, Laos, Thailand, Malaysia and south to Indonesia (Sumatra, Java, Sulawesi). Knutson et al. (1975) listed this species from Nepal for the first time in the literature based on citations in older literature. There is only one taxon from Nepal, listed as Baccha sp. near maculata Walker, which might refer to A. nubilipennis, but this single female has the thorax, scutellum and pleura shining black; thus, it cannot be A. nubilipennis. This author has checked all the literature used by Knutson et al. (1975) and additional works, and has not found any citation of A. nubilipennis from Nepal. Consequently, the presence of A. nubilipennis in this country is questionable.

Type locality

Sri Lanka: Central Province, Kandy, 07°17 ʹ N, 80°38 ʹ E.

Material examined

Type material. Lectotype, male, deposited in The Natural History Museum, formerly British Museum (Natural History) (London, United Kingdom) and labelled: ‘ Type // ♂ ’ [round, red margin] ‘ LECTO- // TYPE // ♂ ’ [round, purple margin] ‘ Kandy. // Ceylon. // 28. vi.92. // circa 1,700 ft. // Col. Yerbury. // 92. – 192. ’ ‘ Baccha // nubilipennis // Aust’. // Type ♂ ’ [on the reverse of previous label, handwritten] ‘ LECTOTYPE ♂ // Baccha // nubilipennis AUSTEN’ [yellow] ‘ Asiobaccha ♂ // nubilipennis // (Austen) // K. D. Ghorpade det. 19 83’, ‘ LECTOTYPE // Asiobaccha // nubilipennis // de s. X. Mengual 20 14’ [red] (specimen photographed). Paralectotype: ‘ PARA- // LECTO- // TYPE // ♂ ’ [round, blue margin] ‘ Kandy. // Ceylon. // 30.v.92. // circa 1,700 ft. // Col. Yerbury. // 92. – 192. ’ ‘ Baccha // nubilipennis // Aust’. ’ [on the reverse of previous label, handwritten] ‘ PARALECTOTYPE // Asiobaccha // nubilipennis // det. X. Mengual 20 14’ [yellow] [1♂, BMNH].

Nontype material. More than 100 specimens from Sri Lanka, India (Kerala, Tamil Nadu, Karnataka), Japan (Ryukyu Islands), Taiwan, Vietnam, Laos, Thailand, Malaysia and Indonesia (Java, Sulawesi, Sumatra). Specimen photographed: TAIWAN: Koshun, 25 April – 25 May 1918, J. Sonan, K. Miyake, M. Yoshino [1♀, CNC]. Male genitalia drawing from specimen: INDIA: Tamil Nadu, Burliar, 860 m, 23 October 1975, Viraktamath [1♂, ZFMK].

Remarks

Austen (1893) described this species from several male and female specimens collected by L.C. Yerbury in Sri Lanka. He stated that the typical specimens are a male collected on 28 June 1892 and a female collected on 25 May 1892. In the BMNH, there were two males, and the specimen collected on 28 June 1892 by Yerbury is designated here as the lectotype to fix and ensure the universal and consistent interpretation of the name.

At the BMNH there was another female specimen collected by E.E. Green from Sri Lanka with the ‘ paralectotype ’ label. The present author does not consider it a paralectotype because Austen (1893) did not list this specimen among the studied material.