Figs 11, 12, 14, 15, 17, 18, 27, 33

Phalaena Bombyx corylina Martyn, 1797: pl. 26 fig. 70; syn. n., nomen oblitum. Diphthera deridens Guenée, 1852 in Boisduval & Guenée 1852: 35 pl. 3, fig. 8. Acronycta circulifera Walker, 1857: 709.

Charadra contigua Walker, 1865: 446.

Charadra ingenua J. B. Smith, 1906: 10; syn. n.

Charadra sudena J. B. Smith, 1908: 80.

‡ Charadra deridens ab. nigrosuffusa Strand, [1917]: 46; unavailable

Charadra deridens form fumosa Draudt, in Seitz 1924: 19.

Type material. Phalaena Bombyx corylina – Type locality: [USA:] Georgia. Unstated number of types [unknown]. Note – this name was transferred to the genus Charadra by Poole (1989) and therein stated to probably be conspecific with C. deridens. Bombyx corylina has otherwise not appeared in the published literature in the past 200 years, nor since Poole’s (1989) mention. To preserve the name Charadra deridens for a well-known North American species, which has appeared in many publications since its description, we treat Bombyx corylina Martyn as a nomen oblitum and Diphtera deridens Guenée as a nomen protectum under the provisions of Article 23.9.2 of the International Code of Zoological Nomenclature (1999). Th e suppression of the name corylina requires that 1) it has not been used as a valid name after 1899 (the usage of the name in Poole (1989) must not be taken into account under the provisions of Article 23.9.6), and 2) the junior synonym (deridens) has been used as the presumed valid name, in at least 25 works, published by at least 10 authors in the immediately preceding 50 years and encompassing a span of not less than 10 years. A search of the Zoological Record indicates that both provisions are met.

Diphthera deridens – Type locality: North America.

Acronycta circulifera – [USA:] East Florida. Female holotype. BMNH; photograph examined.

Charadra contigua – [USA:] Georgia. Male holotype. BMNH; photograph examined.

Charadra ingenua – Type locality: [USA:] Durango, Colorado. Male lectotype (Fig. 4) designated by Todd (1982). AMNH; examined. Note – Charadra ingenua has been a “ghost species,” rarely mentioned in the literature and with few specimens in collections. The lectotype is a specimen typical of eastern Colorado C. deridens populations, which are slightly smaller and have less contrastingly marked forewings and paler hindwings than eastern North American C. deridens. Examination of specimens from western Colorado matching the type of C. ingenua are not distinguishable in genital characters from C. deridens, so we place C. ingenua syn. n. in synonymy with C. deri- dens. Specimens from the Guadalupe Mountains of west Texas reported as C. ingenua by Blanchard and Franclemont (1981) are C. moneta sp. n. (see below).

Charadra sudena – Type locality: [USA:] Florida, Miami. Male lectotype designated by Todd (1982). AMNH; photograph examined.

Charadra deridens ab. nigrosuffusa – an unavailable infrasubspecific name.

Charadra deridens form fumosa – Type locality: None given [unknown].

Diagnosis. C. deridens can be identified by it being the only Charadra species throughout its range, and is characterized by the typically monochromatic colouring of the forewing (lacking brown shades), and the black scaling in the orbicular spot (diffuse and brownish in C. moneta). Charadra deridens may prove to be sympatric with C. moneta in New Mexico and western Texas, but the two can be distinguished by the more contrasting ‘pupil’ of the orbicular spot in deridens, and the white-grey rather than brownish forewing colour of moneta, as well as by the genital differences presented in the diagnosis of C. moneta.

Distribution and biology. Widely distributed, from Nova Scotia to British Columbia (not yet recorded from Alberta), south to Florida, Texas (Knudson and Bordelon 2004) and northeastern New Mexico (Raton, Colfax Co.). The larva, illustrated by Wagner (2005), feeds primarily on beech, oak, and white birch.

Remarks. Although quite consistent in appearance within a given geographic region, there is a moderate amount of variation in phenotypes across its range, and a melanic form (Fig. 16) occurs in the northeastern part of its range (Klots 1968). The palest specimens are from Atlantic Canada (Fig. 11, 15), particularly Nova Scotia. Kentucky specimens are on average smaller with a slight brown cast and reduced white scaling (Figs 14, 18), whereas Colorado specimens are paler overall with less contrasting forewing markings (ingenua, Fig. 12).

Four specimens of C. deridens from Ontario and Kansas expressed three haplotypes, differing by less than 1%, and at least 2.5% divergent from three C. moneta samples.