TL: 7.50–9.00 mm; TW: 6.00–8.00 mm; TL/TW: 1.07–1.50; PL/PW: 0.45–0.48; EL/EW: 0.88–1.03. Male: Form (Fig. 1a, b, c) broadly oval, dorsum convex, broadest a little before middle of elytra, elytra nearly as wide as long; glabrous except head with silvery white hairs. Dorsum bright lemon yellow to yellowish green except lateral margins of pronotum and elytra transparent, pronotum with an indistinct M-shaped marking. Antennae, mouthparts and ventral side yellowish brown; ventral surface covered with short, silvery white pubescence. Head with clypeal margin truncate between lateral projections; eyes prominent, inner ocular margins anteriorly distinctly divergent. Antenna 11-segmented, elongate, >2× as long as interocular distance, with a moderately long 3-segmented club, terminal antennomere oval, apically flattened. Punctures on head shallow, separated by 2–5 diameters, interspaces between punctures with distinct, reticulate microsculpture. Pronotum finely punctate, punctures separated by 2–5 diameters, interspaces with strong, reticulate microsculpture on disc, more obsolete towards lateral margins. Elytral punctures slightly larger and more widely spaced than those on pronotum, separated by 3–6 diameters, interspaces shinier than that on pronotum, with microsculpture; lateral expansions of elytra with larger and coarser punctures. Prosternal intercoxal process convex, without carinae. Mesoventrite medially semi-circularly emarginate. Metaventrite with discrimen. Epipleuron wide, deeply concave, distinctly descending externally. Meso- and metatibiae with a pair of apical spurs. Tarsal claws appendiculate. Abdominal postcoxal line (Fig. 2a) very short, not reaching posterior margin of ventrite 1. Posterior margin of ventrite 5 shallowly and widely emarginate, that of ventrite 6 medially more deeply emarginate. Male genitalia (Fig. 2a, b, c, d, e) as illustrated, tegmen in lateral view (Fig. 2b) with parameres longer than penis guide, apices covered with dense, elongate hairs; penis guide in inner view (Fig. 2c) elongate, cylindrical in anterior half, posterior half distinctly narrowed, triangular with a tubular apex; penis (Fig. 2d, e) with a distinct capsule, strongly arched, apically produced into a strongly curved process (Fig. 2e).

Female: Externally similar to male. Female genitalia (Fig. 2f) as shown, spermatheca bulky, sperm duct somewhat abruptly thickened a little after basal third; infundibulum present, composed of a pair of apparently lamellate structures.

This species is externally similar to Calvia albida, Calvia flaveola Booth and Calvia championorum Booth. It is particularly close to Calvia albida (Fig. 1d) in having a mottled elytral pattern with several smaller spots. Both Calvia albida and Calvia explanata share a similar distribution range in India and are found in northeastern India and Nepal. Calvia albida is also distributed in China (Ren et al. 2009; Yu 2010). Calvia explanata differs from Calvia albida in having a distinctly wider, more circular body outline and explanate elytral margins. The male genitalia are also distinctive with the penis guide narrower and more elongate and the penis with an elongate, membranous apical process. In Calvia albida, the penis guide is distinctly broader up to a little beyond middle and the posterior half is much less narrowed and the penis has a more robust basal capsule and the apex is different. The male genitalia of Calvia albida were illustrated by Bielawski (1972) and Ren et al. (2009). The female genitalia in Calvia albida (Fig. 3) has a distinctly bulkier spermatheca (Fig. 3b) with a long, more or less uniformly thick sperm duct and the infundibulum is differently structured.

The specific epithet is an adjective of Latin origin and refers to the explanate elytral margins.

India (Sikkim; West Bengal). Nepal.

This species seems to have an arboreal habitat like many other species of Calvia (Booth 1997) as some of the specimens examined were collected on Alnus sp. (label data).

Calvia is not a very well defined genus with some members having aberrant characters. This species is placed in Calvia by the following combination of characters as per the diagnosis given by Gordon (1985): anterolateral angles of clypeus produced forward, lateral margins of pronotum and elytra explanate, middle and hind tibial apices with a pair of spurs each, abdominal postcoxal line incomplete, and tarsal claws appendiculate. Gordon (1985) in his diagnosis of Calvia mentioned that female genitalia lack infundibulum, but female genitalia of many Oriental species of Calvia, including Calvia explanata, have a distinct infundibulum.