Type material : syntype female, “SYNTYPE (blue bordered circular label)/ Bhamὀ, Birmania, Fea, VII.1886/ Jacoby Coll. 1909-28a/ Nodostoma subcostatum Jac./ abdomen missing, S.L. Shute 1976/NHMUK014016383” (BMNH). Other material: 64016/Birmah, Momeit/Doherty/Fry Coll. 1905-100, 1 ex.; Tharrawaddy, Burma/ Andrewes Bequest 1922-221/ Nodostoma subcostatum Jac., 1 male with genitalia glued to the same card; Assam, Sudiya/ Doherty/ Fry Coll. 1905-100, 1 male; Assam, Patkai Mts./ Doherty/ Fry Coll. 1905-100/ Jacoby det., 1 ex; Thailand, Lot 1830, Nakhonratchasima, June 15, 1912/24/To B.M. List 153.10/ C.I.E. Coll. A1720/ Pres. By Com. Inst. Ent. B.M.1967-2, 2ex. (BMNH); S.INDIA, Mysore, Vittal 1964, Arecanut Res. Stn., on banana/ C.I.E. Coll. No.19658, 2 ex; Deccan/ 67.56, 1 ex; NEPAL: Rampur, 14.vii.1981, Ex. Banana, 6 ex; NEPAL: Dhunibesi, 22.vi.65, Banana, Dept. Agric. C.I.E. A.573, Col.161/ Pres. By Com. Inst. Ent. B.M. 1966-22, 2 females and 2 unsexed; 61647/ Doherty/ Assam, Patkai Mts/ Fry Coll. 1905-100, 4 ex; Bacan, N. India/ 67.56, 3 ex.; Calcutta / Atkinson Coll. 92-3, 2 ex; Doherty/ Tenesserim, Mergui/ Fry Coll. 1905-100; W. Almora Divn., Kumaon, UP, Aug. 1917, HGC/ E8/ H.G. Champion Coll. B.M. 1953-156, 4 ex; Lansdowne Division, UP, India, F.W.C./ H.G. Champion Coll. B.M. 1953-156, 1 ex.; Ind./ Baly Coll., 1 ex.; Khasis/ Coll. Kraatz/ Pres. by Imp. Inst. Ent. BM 1938-351/ Nodostoma occipitale Jac., Det. G.E. Bryant, 1 ex. (BMNH). India: Assam: 7 ♂ and 5 ♀ Balipara 74 m msl/26°49'56"N, 92°46'41.1"E/17.v.2019/K D Prathapan Coll.; 3 ♂ Jorhat /19–22.xi.2007/ Prathapan K D Coll.; 4 ♂ and 10 ♀, Assam: Dergaon, 26°42'01.00"N, 093°54'01.26"E/2.x.2018, R. Thanigairaj; Assam: 2 ♂, 2 ♀ Nameri Nat. Park 85 m msl/ 26°55'27.4"N, 92°49'38.9"E/17.v.2019/ K D Prathapan Coll.; Assam: 17 ♂, 13 ♀ and 7 unsexed, Tezpur 72 m msl/ 26°37'33.4"N, 92°48'41.5"E/19.v.2019/ K D Prathapan Coll.;. 25 ♂ and 14 ♀, Assam: Kaziranga, Kohora 70 m msl/ 26°35'29.6"N, 93°23'56.1"E/18.v.2019/ K D Prathapan Coll./Ex Banana; 2 ♂ same data, except Host Canna sp.; Meghalaya: 11 ♂, 13 ♀, Barapani/25°41'17.6"N, 91°55'5.1"E/5.vi.2013 993 m/Prathapan K D Coll./Ex. Banana; 3 ♂, 1 ♀, Meghalaya: Nongpoh 587 m msl/25°50'34.4"N, 91°52'34.4"E/22.v.2019/ K D Prathapan Coll.; 1 ♂, 6 ♀ Meghalaya: Cherrapunjee 1426 m msl/ 25°17'11.0"N, 91°43'07.8"E/21.v.2019/ K D Prathapan Coll.; 3 ♂, 3 ♀ Meghalaya: Umroi/2.xii.2007/Prathapan K D Coll.; 4 ex, Meghalaya: Jorabat, 04.x.2018, 26°04'59.52"N, 091°52'36.59"E, R.Thanigairaj; Meghalaya: 2 ex, Umiam/19.vii.2019/D. M. Firake/Ex ginger; 3 ♂ and 10 ♀, West Bengal: Cooch Behar, x.2016, B. Padmanaban; Uttar Pradesh: 4 ♂, 9 ♀ Faizabad Dist, 27°37'06.96"N, 081°36'29.54"E, 12.xi.2018, J. Poorani; Bihar: 6 ♂ and 1 ♀ Bhagalpur, 6.iii.2016, B. Padmanaban; Bihar: Falka, 11–12.x.2017, B. Padmanaban; Odisha: 4 ex, Bhubaneshwar, 29.v.2015, Sangeetha.

Body oblong; head mildly sulcate above eyes; antennae filiform or distal antennomeres widened; pronotum wider than long, widest posteriorly, lateral margins often angulate; anterior margin of proepisternum concave; legs long, all femora dilated, minutely dentate ventrally, tibia longitudinally sulcate with a sharp ridge along dorsal side; intermediate and posterior tibiae emarginated preapically; metatibia with a pair of short apical spines; prosternum broader than long. Claws appendiculate; bursa sclerites present in female genitalia.

Basilepta makiharai Kimoto, described from Nepal, is stated to “resemble B. subcostata in having the elytron with humeral ridge but differs by its shorter body length and in having the surface of vertex finely shagreened” (Kimoto 2001: 26). It is generally pitchy black to dark reddish brown with entirely yellowish-brown antenna. Basilepta viridipennis (Motschulsky), another species widely distributed in Southern Asia and erroneously reported as the banana fruit-scarring beetle from India and Bangladesh, is also externally similar to B. subcostata, but its antenna is almost fully blackish except for the first four antennomeres and the posterolateral callosity of pronotum does not project beyond lateral margin, and hence, the posterolateral corners of pronotum are obtuse and not angulate as in B. subcostata. Besides, the elytra are metallic green to violaceous and shinier and lack a distinct lateral costa.

Nodostoma obscurum Jacoby, 1908 and Basilepta sakaii Takizawa, 1987 were listed as synonyms of B. subcostata in the catalogue of Nepalese Chrysomelidae by Medvedev and Sprecher-Uebersax (1997: 288), but they did not mark it as a new synonymy. This appears to be incorrect because the type of N. obscurum is not even morphologically similar to N. subcostatum, whereas B. sakaii is a smaller insect according to the description (Alexey Moseyko, personal communication).

Length 2.34–3.00 mm, width 1.36–1.86 mm, 1.6–1.7× longer than broad. Body (Fig. 1a–c) oblong ovate, shiny. Colour highly variable from red-brown to dark blue, black, or their mixtures without any spots, stripes or maculations; head entirely red-brown to tinted black except vertex red-brown, palpomeres light yellow to brown, some specimens with apex of last palpomere black; basal 4–6 antennomeres light brown and rest gradually turning piceous to black; colour of pronotum and elytra varies from red-brown or dark blue to shiny black, pronotum concolorous with elytra or not, general color of legs red-brown to dark brown or testaceous, tibia distally and tarsomeres darker.

Three major color morphs and their intermediates were commonly observed:

1. Head and pronotum red-brown; elytra blue, blue-black, dark green, or black; all ventrites dark (Fig. 1a). A syntype, images of which were made available by the Museum of Comparative Zoology (http://140.247.96.247/mcz/Species_record.php?id=9291), belongs to this category.
2. Entirely red-brown, except distal antennomeres, legs and palpi piceous to black (Fig. 1c);
3. Entirely dark blue, blue-black, dark green, or black (Figs 1b, 2), except head medially red-brown; metasternum and abdominal ventrites piceous to black; all entirely dark variants observed were females.

Head (Fig. 3a, b) distinctly punctured with impunctate areas on vertex and frons; punctures bold, slightly smaller than those on pronotum. Coronal suture weak but evident. Supraorbital pore adjacent to dorsal margin of eye, rounded, with a long seta. Orbital sulcus with deep, bold punctures. Frons hardly differentiated from vertex, supra frontal sulcus weak. Frons with a few bold punctures, impunctate medially. Antennal calli trapezoidal, raised; supracallinal sulcus well developed with a few bold punctures. Clypeus forms narrow transverse band with strongly concave anterior margin; frontoclypeal suture with a few small punctures. Labrum broader than long, with a pair of broadly placed setose punctures in middle and a pair of setae anterolaterally; anterior margin with thick short setae on either side of middle, apical margin emarginate medially. Antennae hardly extend up to middle of elytra; first antennomere thick, longer than second; second antennomere thinner than first, thicker than 3^rd and 4^th separately; 5^th onwards antennomeres progressively thicker; basal four antennomeres smooth, shiny, sparsely setose; distal seven thickly covered with short pointed setae, proportion of antennomeres as follows: 1 : 0.80 : 1.13 : 1.33 : 1.27 : 1.20 : 1.20 : 1.27 : 1.20: 1.13 : 1.33.

Compound eyes with inner margin feebly emarginate, transverse diameter about 1.4–1.5× vertical. Distance between eyes 1.8× distance between antennal sockets, shortest distance between compound eye to adjacent antennal socket about 3.5× distance between antennal sockets. Mandibles with two large denticles; maxillary palpi three-segmented excluding palpifer; last palpomere longest, penultimate palpomere less than half length of last palpomere. Labial palpi with three palpomeres, excluding palpiger, first palpomere being shortest and last longest.

Pronotum (Fig. 3c, d) about 1.6× broader than long, posteriorly 1.6–1.7× wider than anteriorly, somewhat trapeziform in outline, narrowed anteriorly, with posterolateral callosity laterally projecting beyond lateral margin, hence posterolateral corners appear sharply angulate, lateral margins angulate at posterior one-third presenting octagonal appearance, densely punctate, punctures larger than those on head and smaller than those on elytra, posterior margin gently lobed in middle, anterior sulcus and posterior sulcus distinct with a row of punctures, posterior sulcus deeper than anterior. Scutellum wider than long, broadly rounded posteriorly, sparsely and minutely punctate. Elytra 1.2× longer than wide, punctate striate, punctation weaker towards apex, punctures regular post medially with 10 striae; partially confused and semiregular in anterior half of elytra due to incomplete or broken striae; distance between punctures in a row less than distance between adjacent rows; extreme lateral row of elytral punctures regular, complete, extending up to apex; second row merged with first row from anterior one-fourth to middle of elytra; third row arising from humerus extending up to apex of elytra; interstice between 2^nd and 3^rd lateral rows distinctly costate, extending as far as middle of elytra or beyond, costa variable in prominence, strongly convex and sinuate in the syntype female (Fig. 2b) (BMNH, examined), but only moderately prominent in most of the Indian material examined. Humeral calli well developed, post basal depression shallow but distinct; basal calli distinct, vary in prominence. Elytral apex narrowly convex. Epipleura outwardly oblique with sparse and fine punctures, narrowing beyond proximal one-third, hardly reaching elytral apex.

Prosternum broader than long, broader posteriorly than anteriorly, with bold punctures, posterior margin straight; mesosternum nearly twice as broad as long with a few punctures smaller than those on prosternum. Proepisternum depressed; hypomeron with bold punctures. Legs long; all femora dilated, minutely dentate ventrally beyond middle (Fig. 3e, f); tibia (Fig. 3f) with eight sharp carinae, variable in prominence: three each dorsally and ventrally, one each on either side laterally. Tarsomeres ventrally fringed with diverse forms of setae, basitarsomere with closely arranged capitate setae bordered by long pointed setae in males and only pointed setae in females, second tarsomere ventrally with pointed setae, bilobed third tarsomere with triangular or inverted arrowhead-shaped setae ventrally.

Ventrites sparsely punctate, pubescent; first ventrite medially longer than following two combined, ventrites 3 and 4 subequal, shorter than 2 and 5 separately which are subequal, last ventrite hardly sexually dimorphic, last tergite without longitudinal groove medially.

Male genitalia: aedeagus in lateral view (Fig. 4a, c, e, h, k, m, n, o) sharply bent almost at right angle near base of aedeagus proper, apical portion acutely narrowed and slightly recurved dorsally; in ventral view (Fig. 4b, d, f, g, i, j, l), depressed along ventral surface, apex narrowed forming obtuse denticle; apical opening wide, partially covered by a lamina with a pair of sclerotized stripes fused basally and joining dorsal surface. Tegmen (Fig. 4q) flat, membranous, lightly sclerotized, bilobed distally, proximally with a pair of arms which turn narrowed and encircle base of aedeagus proper. Spiculum gastrale (second spiculum of Jolivet and Verma 2008) Y-shaped, sclerotized. Tergite VIII semicircular with spindle-shaped sclerotization on either side, with short setae apically. Spiculum reclictum (sensu Slipinski and Escalona 2013) spoon-shaped, distally dilated (Fig. 4p).

Endophallus (Fig. 5a) long, membranous, tubular, about 3.7–3.9× longer than aedeagus proper; with three distinct regions: basal phallomere (BP), median phallomere (MP), and apical phallomere (AP); basal phallomere (Fig. 5b) very short with a lateral lobe on either side, followed by two inwardly curved central sclerites (CS) dorsally; median phallomere (Fig. 5c) longest, tubular, with setae or hair like spicules, a few circular spicules present near apical region; apical phallomere (Fig. 5d) much wider than other two regions, asymmetrical, with spicules varying in shape such as triangular, angular, oval; apical region proximally with three minute lobes facing median phallomere, apex with large lateral lobes and several smaller lobes medially.

Female genitalia (Fig. 6) with spermathecal capsule sickle-shaped (Fig. 6a, b), proximal portion very short, constricted medially, dumbbell-shaped where spermathecal duct and spermathecal gland join side by side, distal portion sickle-shaped, sharply curved, subacutely narrowed towards distal end; spermathecal gland long and tubular, length of spermathecal capsule 7.7× its maximum width. Bursa copulatrix (Fig. 6c) sac like, longer than wide, with a long bursa sclerite (BS) on either side, spermathecal duct joins bursa copulatrix between these sclerites, median oviduct attached on the other side of bursa copulatrix. Ovipositor (Fig. 6d) elongate, sclerotized distally, with almost 10–16 long setae, stylus absent; 8^th sternite and 8^th tergite fused laterally to form a membranous cylinder with mild sclerotizations laterally (Fig. 6f) ; 8^th sternite with a long tignum sensu Konstantinov, 1998 (spiculum ventrale sensu Slipinski & Escalona, 2013) longer than ovipositor (Fig. 6e); collateral gland (CoG) present (Fig. 6g).

India [Karnataka (new record); Delhi (Batra 1952); Uttarakhand; Uttar Pradesh; Bihar; Odisha; West Bengal; Sikkim; Assam; Manipur; Meghalaya]. Bangladesh. Myanmar, Thailand, Laos, Cambodia (Kimoto and Gressitt 1982; Vansilalom 2016); Nepal (Medvedev 1990; Sprecher-Uebersax 1997; Kimoto 2001). A distribution map is available at this link: https://www.google.com/maps/d/edit?hl=en&mid=1QgHVswL3eaPJ2soJ16_R5BTkIu8mRM6z&ll=23.692266951458954%2C78.67937627596257&z=6.

Musa spp. (Musa sapientum, M. acuminata; Musaceae, Zingiberales) are principal hosts. Beetles were observed feeding on ginger (Zingiber officinale Roscoe; Zingiberaceae, Zingiberales) in Meghalaya (D.M. Firake, personal communication). In Assam, northeastern India, adult beetles were observed feeding on Canna indica L. (Cannaceae, Zingiberales) and turmeric (Curcuma longa L., Zingiberaceae) and characteristic feeding marks were observed on the latter. This is the first documentation of other hosts of B. subcostata besides banana. Adults were also found to be resting on taro (Colocasia sp., Araceae, Arales) (unpublished data).

The adult beetles are most active during the monsoon and post-monsoon seasons and summer. They are nocturnal and usually found hiding inside the leaf whorls and come out only when disturbed. They feed on the young unfurled leaves (Fig. 7a), leaf petioles (Fig. 7d, e), and stems of banana, and the emerging leaves (Fig. 7b, c) are badly scarred. Feeding damage was also observed on flowers (Fig. 7f) and bracts (Fig. 7g), as well as young, developing fruits (Fig. 7h, i). For more images of the damage symptoms on cultivated banana, see the website of ICAR-National Research Centre for Banana (2019). In severe cases, the developing bunches and fruits (Fig. 7j–l) are so badly scarred that they lose their market value.

Eggs are laid in the soil and the larvae feed on the roots of grasses and other weeds. Pupation takes place in the soil. Emerging adults feed on young leaves and fruits. Adults hibernate during winter. Seasonal incidence and population dynamics of fruit scarring beetles have been studied from some parts of India, including Assam (Mishra et al. 2015) and Bihar (Ahmad et al. 2010; Sah et al. 2018).

Mukherjee et al. (2006) reported that meteorological factors accounted for about 85% of the beetle incidence in Bihar (India) and minimum temperature and maximum relative humidity had a positive and significant effect on scarring beetle populations. Though damage due to scarring beetles is believed to be mainly cosmetic, the fruit quality is also badly affected. Zahan et al. (2001) and Sah et al. (2018) reported that scarring beetle infestation significantly delayed fruit ripening, reduced the fruit weight, and adversely affected the skin colour and thickness of fruits and the taste and smell of the pulp. This damage considerably affects the consumption value.

In Uttar Pradesh, North India, adults of the predatory beetle, Paederus fuscipes Curtis (Coleoptera, Staphylinidae), were found to be commonly associated with B. subcostata. Natural epizootics of entomofungal pathogens, such as Beauveria bassiana, are commonly observed on B. subcostata in the northeastern region of India (Fig. 8) and exert some control in the post-monsoon months.

Type material of Nodostoma occipitale Jacoby: 62590/ Type (red bordered circular label)/ Doherty/ Tenesserim, Mergui/ Fry Coll. 1905-100/ Nodostoma occipitale Jac., Type (blue label)” (BMNH). Other material: Fea/ Birmah, Carin Cheba/ Fry Coll. 1905-100/ NHMUK0114016244, 1 ex; Doherty/ Tenesserim, Javoy/ Fry Coll. 1905-100/ NHMUK014016300, 1 ex (BMNH).

Basilepta viridipennis (Fig. 9) has been erroneously reported in the literature as a pest of banana in the Indian Subcontinent (India and Bangladesh), and Waterhouse (1993) also listed it as a major pest of banana in Southeast Asia. All reports of its occurrence in northeastern India (Das and Baruah 2018), Bangladesh (Ahmed 1963; Zahan et al. 2001, 2003, 2004; Rahman et al. 2004), and Thailand (Wongsiri 1991) are most likely to refer to B. subcostata. The type of N. occipitale Jacoby (Fig. 9a, b) (BMNH, examined), a synonym of B. viridipennis, has only a superficial resemblance to B. subcostata and can be easily separated from the latter by the pronotum forming an obtuse angle posterolaterally (Fig. 9b) and its lateral margins abruptly converging anteriorly in almost a straight line. Besides, pronotal punctures in B. viridipennis are smaller than average elytral punctures and finely and more closely impressed on lateral part and more sparsely and finely so on median and anterior parts. Basilepta viridipennis is of variable coloration and includes reddish, brownish, bluish, greenish, violaceous, and blackish forms. Medvedev (2006) designated a lectotype for N. viridipenne and synonymised Basilepta frontalis (Baly) with it, as he found the types of both species were identical.

India, Nepal, Myanmar (= Burma), Thailand, Laos, Vietnam, Hainan, Malaya, Sumatra.

Type material of Sphaeroderma varipennis Jacoby: “Type (H.T.) (red bordered circular label)/ Carin Cheba, 900–1100 m, L. Fea, v.XII.88 / Jacoby Coll. 1909-28a / Sphaerod. varipennis Jac. (blue label)” (BMNH); Others: “Sumatra/ Jacoby Coll. 1909-28a/ variepennis Jac. In B.M. Coll. C.M.F. Von Hayek det. 1967/ Bhamoina varipennis (Jacoby), G. Scherer det. 1967” (BMNH). India: Assam: 5♂, 6♀♀, Balipara 74 m msl; 26°49'56.0"N, 92°46'41.1"E; 17.V.2019; K. D. Prathapan Coll. (KAU); Meghalaya: 3♂, 8♀ Barapani 993 m msl; 25°41'17.6"N, 91°55'5.1"E; 5.vi.2013; K. D. Prathapan Coll. Ex banana (KAU); Meghalaya: 11♂, 16♀, Ri Bhoi Dst., Saiden 540 m msl; 25°52'41.0"N, 91°53'1.4"E; 4.vi.2013; K. D. Prathapan Coll. Ex banana (KAU); Meghalaya: 5♂, 2♀, Nongpoh, 587 m msl; 25°50'34.4"N, 91°52'34.4"E; 22.v.2019; K. D. Prathapan Coll. (KAU).

The genus Bhamoina closely resembles Sphaeroderma (see below for the generic diagnosis of Sphaeroderma). Bhamoina acutangula (Jacoby), the type species of the genus, was originally described in Sphaeroderma. Bhamoina can be easily separated from Sphaeroderma by the anteriorly produced anterolateral corners of pronotum (in Sphaeroderma, the anterolateral corners of pronotum are not produced forward, or only slightly produced). Sphaeroderma varipennis Jacoby, treated as a synonym of B. varipes by Scherer (1969), is bicolored (Fig. 11a) with the eltyra fully black and the head and pronotum reddish. It has a slightly more robust body form, and the anterolateral corners of pronotum (Fig. 11b, c) are less produced and somewhat obtusely rounded compared to those of B. varipes.

Scherer (1969) gave a key to the Oriental species of Bhamoina. Sphaeroderma varipennis has been known to be a pest of banana in Thailand, and adults defoliate banana (Hill 2008). Dean (1978) recorded “Sphaeroderma veripennis” on banana in Laos. Although B. varipes is distributed in India, there has been no previous records of its host plant association from India.

Entirely red-brown (Fig. 10a, b), except eyes and distal portion of mandibles black. Elytra darker in a few examples. Proximal 5–7 antennomeres lighter than distal ones. Anterolateral corners of pronotum, palpi, fore- and midfemora, tarsomeres, and last abdominal ventrites often lighter than dorsum.

Length 2.71–3.41 mm, width 1.97–2.80 mm, 1.34× longer than broad. In lateral view vertex weakly convex, forming a concavity where it joins frons; frons strongly arched, joining clypeus at an obtuse angle. In frontal view vertex moderately flat, sparsely punctate with a mixture of small and minute punctures. Supraorbital pore circular, without shallow groove surrounding it, placed just above orbital sulcus, two or three smaller punctures anterior to supraorbital pore present. In frontal view (Fig. 10c), frontal ridge broad and raised between antennal sockets; narrowed dorsally entering between antennal calli; ventrally narrower than dorsally; frontolateral area anteriorly with a few setae; anterofrontal area flat, not forming ridge, with long and short setae. Antennal calli transverse-oblique, trapezoidal, slightly higher than vertex, narrowly separated dorsally; anteromesal ends acutely angulate, entering into interantennal space. Supracallinal sulcus deep, gently convex, oblique, narrower than orbital sulcus. Suprafrontal, supraorbital, supraantennal sulci well developed, all weaker than supracallinal sulcus. Distance between antennal sockets 1.57× diameter of a socket, antennal sockets separated from adjacent eye by a distance 0.38× transverse diameter of a socket. Labrum wider than long, dorsal surface convex anteriorly, anterior margin convex, with three pairs of labral setae arranged in a transverse row. First antennomere longer than second and third combined, second a little longer than third and fourth separately, sixth onwards antennomeres progressively thickened. Proportionate length of antennomeres I to XI: 1 : 0.48 : 0.41 : 0.52 : 0.56 : 0.44 : 0.59 : 0.52 : 0.52 : 0.52 : 0.8. Maxilla with penultimate palpomere thicker and longer than last and preceding palpomeres separately. Labium with penultimate palpomere thickened, subequal in length to thin, pointed last palpomere.

Pronotum (Fig. 10d) convex, distinctly narrowed anteriorly, 0.30× as long as wide, posteriorly 1.65–1.76× wider than anteriorly, profusely, uniformly covered with small punctures. Pronotal punctures as small as half of elytral punctures. Lateral margin weakly convex proximally, gently concave at anterolateral seta bearing pore; broader anteriorly than posteriorly. Anterior margin deeply concave, except gently convex in middle. Posterior margin bisinuate, forming a distinct lobe in middle. Anterolateral callosity (Fig. 10e) projecting forward on either side of head; seta bearing pore on dorsal posterior face of callosity. Posterolateral callosity not protruding laterally, with seta bearing pore on lateral face.

Scutellum triangular, acutely angulate posteriorly, shiny, flat on top, minutely punctate. Elytra as wide as pronotum at base, widened postbasally, lateral margin entirely visible in dorsal view. Elytral apex convex. Elytral punctures confused in mesal half, tend to form rows in lateral half, outermost punctures forming a regular row. Each elytral puncture surrounded by a dark halo, distance between adjacent punctures less than diameter of one puncture, including dark halo.

Maximum width of elytral epipleura subequal to that of midfemur. Epipleura subhorizontal, visible in lateral view, widest at proximal one-fourth, gradually narrowing till distal one-third and then abruptly narrowed, hardly reaching apex. Prosternum gently depressed on top, setose, coarsely but shallowly punctate; minimum distance from anterior margin of prosternum to coxal cavity less than half of minimum width of prosternal intercoxal process; prosternal intercoxal process longer than wide, narrowed in middle, widened apically, posterior margin concave. Mesosternum transverse, nearly three times wider than long, with concave posterior margin; metasternum profusely setose medially, coarsely punctate. First abdominal ventrite profusely setose medially, coarsely punctate; in length, medially subequal to next three combined. Last ventrite a little longer than preceding two combined. Last visible tergite medially with a broad longitudinal groove not reaching apex.

Foretibia without apical spine. Mid- and hind tibiae with apical spine. First pro-, meso-, and metatarsomeres distinctly wider in male than in female; with capitate setae ventrally in male and pointed setae in female. Posterior margin of last ventrite entire in female; forms a lobe notched on either side, in middle in male. Last ventrite internally with a longitudinal apodeme along mid-line in male (Fig. 12a), externally visible as a dark line; apodeme absent in female (Fig. 12b).

Male genitalia with aedeagus in lateral view (Fig. 12f) curved, apex acutely pointed, recurved dorsally. In ventral view (Fig. 12g), aedeagus with a longitudinal depression along middle of ventral side, depression being stronger distally; aedeagus narrowed apically forming a triangular denticle. Dorsal opening (Fig. 12h) partially covered with three laminae.

Female genitalia with spermathecal receptacle (Fig. 12e) oblong, widest in middle, narrowed towards both ends, 2.2× longer than broad. Vaginal palpi (Fig. 12c) medially fused, both together 1.75× broader than long, posterior margin deeply emarginate with a seta on either side. Tignum (Fig. 12d) channeled along middle, posterior membranous area broadened greatly with posterior margin emarginate medially with a few short setae; tignum gently broadened anteriorly.

Adults feed on the abaxial surface of the leaf lamina, making transverse, narrow linear scars. Feeding by Basilepta subcostata results in much shorter and broader feeding troughs, which is very different from that of Bhamoina varipes.

India (Assam; Meghalaya; Uttarakhand (Dehra Dun)); Myanmar; Nepal (Medvedev 2000); Vietnam; China (Dӧberl 2010); Sumatra; Laos.

Unidentified species of Sphaeroderma Stephens have been reported from Laos as defoliators of banana (Dean 1978; Hill 2008; Vansilalom 2016). We collected a new species of Sphaeroderma feeding on banana from the state of Meghalaya, northeastern region of India, during our surveys, which is described and illustrated here.

Small to medium sized flea beetles, convex and broadly oval. Red brown to black with or without spots or stripes on elytra. Head hypognathous, frontal ridge raised, forming T-shaped ridge with apical margin of head capsule. Antennal calli well delineated by sulci, supracallinal sulcus deep. Pronotum broader than long, without impressions or furrows. Posterior margin bisinuate with a lobe in middle. Procoxal cavity open behind. Anterolateral corners of pronotum not greatly produced forward. Metatibia dorsally flat or concave, with lateral and mesal margins forming ridge. Third tarsomere broad, its anterior margin entire, not bilobed. First metatarsomere short, not longer than next two combined. Intercoxal part of first abdominal ventrite truncate. Vaginal palpi broader than long.

Holotype : ♂: India: Meghalaya: Barapani, 25°41'17.6"N, 91°55'5.1"E; 5.vi.2013, 993 m; Prathapan K D Coll., Ex Banana (BMNH). Paratypes: (17♂, 8♀): India: Meghalaya: Barapani, 25°41'17.6"N, 91°55'5.1"E; 5.vi.2013, 993 m; Prathapan K D Coll., Ex Banana (2 BMNH; 2 USNM; 17 ICAR-NBAIR; 2 NPC; 2 UASB).

This species closely resembles S. mandarensis Jacoby (Jacoby 1900: 123–124), from Mandar in West Bengal, India, especially in size, coloration, structure of head and punctation. However, the pronotum is more narrowed anteriorly than in S. mandarensis. The male genitalia are diagnostic (Fig. 14c–f).

Entirely red-brown (Fig. 13), except distal antennomeres darker. Length 2.97–3.33 mm, width 2.08–2.26 mm, ca 1.40× longer than broad. In lateral view, vertex and antennal calli form a gently curved line with an emargination at their meeting point; frontal ridge forms a strongly convex line that joins anterofrontal ridge at an obtuse angle. In frontal view (Fig. 13b), vertex gently convex on sides, flat in middle, with small punctures and indistinct rugosities. Antennal calli subhorizontal, laterally slightly narrower than medially, about twice wider than long, subquadrate. All sulci surrounding antennal calli well developed. Supracallinal sulcus gently convex. Supraorbital pore circular, with a long seta on a convex tubercle, not surrounded by shallow groove. Frontal ridge sharply raised, narrower ventrally than dorsally. Frontoclypeal suture with closely placed, irregularly arranged long setae. Anterior margin of clypeus straight. Frontolateral area concave, without long setae or bold punctures. Anterofrontal ridge poorly developed, not convexly raised. Distance between antennal sockets 0.84× diameter of a socket, antennal sockets separated from adjacent eye by a distance 0.36× transverse diameter of a socket. Labrum distinctly wider than long, anterior margin convex, with three pairs of transversely arranged setae.

Maxillary palpi with four palpomeres, penultimate palpomere being thicker and longer than last palpomere. First palpomere smallest, second subequal to last. Labial palpi three-segmented with the second palpomere thicker than last, subequal to last in length. Proportionate length of antennomeres I to XI: 1 : 0.61 : 0.57 : 0.61 : 0.74 : 0.70 : 0.74 : 0.70 : 0.70 : 0.70 : 1.09.

Pronotum (Fig. 13c) distinctly narrowed anteriorly, 0.38× times longer than wide, posterior margin 1.59× as wide as anterior margin, anterolateral corners only slightly produced forward, not reaching eye. Lateral margin gently and evenly curved, anteriorly as wide as posteriorly. Anterolateral callosity longer than wide, not forming denticle at pore, pore situated on posterior dorsal face of callosity. Posterolateral callosity not laterally protruding. Disc profusely covered with small punctures, much smaller than those on elytra.

Scutellum as broad as long, obtusely narrowed posteriorly, surface very minutely punctate. Elytra as broad as pronotum at basal margin, widening near humerus. Humerus convex, weakly depressed posteriorly. Elytra with a mixture of small and large punctures. Punctures confused, tend to form uncountable rows. Lateral most row regular, followed by one or two countable adjacent rows. Distance between adjacent punctures smaller than diameter of a puncture. Elytral apex convex. Maximum width of epipleura at anterior one-third; subequal to forefemur in width. Epipleura subhorizontal, narrowing posterior to anterior one-third, not reaching elytral apex.

Prosternum widened posteriorly, posterior margin concave medially, slightly depressed on top, setose with coarse shallow punctures. Mesosternum setose, transverse, with concave posterior margin. Metasternum with moderate sized, deep punctures, thickly setose on either side. First abdominal ventrite longest, 2–4 each shorter than fifth separately; fifth longer than preceding two combined, shorter than preceding three combined. Last visible tergite with a shallow groove along middle, not reaching apex. All tibiae with apical spine.

First pro-, meso-, and metatarsomeres slightly wider with capitate setae ventrally in male. In female, all first tarsomeres ventrally with pointed setae. Posterior margin of last ventrite entire in female, forms a lobe notched on either side in middle in male. Last ventrite internally with a longitudinal apodeme along mid-line in male (Fig. 14a), externally visible as a dark line; apodeme absent in female (Fig. 14b).

Male genitalia (Fig. 14c–f) with aedeagus in lateral view gently bent at middle (Fig. 14c), apex acutely narrowed, recurved (Fig. 14f). In ventral view (Fig. 14d), ventral surface depressed preapically, narrowed to apex, forming a broad denticle. Dorsal side (Fig. 14e) of aedeagus convex, dorsal opening partially covered by a lamina; a characteristic, narrowly elongate, bifid sclerotization present preapically on dorsal side, it laterally extends forming an internal ring around aedeagus.

Female genitalia with spermathecal receptacle (Fig. 14h, i) 1.5× as long as broad, outer margin concave, inner margin convex; pump with unsclerotized denticle apically, horizontal part longer than vertical. Duct twisted proximally, curved over receptacle, reaching a little beyond middle of receptacle. Vaginal palpi (Fig. 14j) narrowly connected medially, both together 2.4× as wide as long. Tignum (Fig. 14g) straight, channeled along middle, gently broadened anteriorly, posterior membranous part broadened greatly with a few short setae along posterior margin, unsclerotized on either side of middle of posterior membranous part.

The specific epithet is a Latin adjective in nominative case in reference to the reddish colour of this species.

India (Meghalaya).

Adults feed on the foliage of banana (Musa spp.).