MORPHOLOGY
External characteristics
Male
Forewing length (mm): 53-58. Wingspan (mm): 78-92.
Forewings: Upperside outer half blackish brown with a narrow, slightly curved submarginal whitish line from near tornus to costa shortly before apex, and with short line of four narrow whitish spots from costa to vein 6 just beyond cell; basal half of wing white with three blackish bands, two from casta to hind margin, one from costa and across middle of cell to cubitus; underside similar, but paler, in basal area white more beige colored Hindwings Margin crenulate with long tail at end of vein 4, about as long as length of hindwing from wing base to beginning of tail; upperside white with grayish and blackish brown markings as follows: narrow band from costa near wing base to space 1b, grayish narrow band from costa to base of space 2, and some morginal and submarginal markings; underside similar, but paler, white inm basal area more beige colored, yellow submarginal spot in space 2.
Female
Forewing length (mm): 60. Wingspan (mm):96.
Similar to male, a bit paler.
Subspecies and variation
Little variation has been reported, yet two subspecies have been recognized.
Similar species
Reminiscent of G. dorcus, but forewing with white bands in dark outer hals and three instead of two bands in basal half.
source: Jan Moonen, peronal communication 2020