Spalgis epius edged with brownish white of a shade paler than that of the ground colour; both wings with an anteciliary dark brown line with on the inner side a similar edging. Forewing, in addition, with an oval white spot beyond the cell. Cilia of both forewings and hindwings of the same shade as the ground colour of the wings. Antenna, head, thorax and abdomen pale brown, club of antennae ochraceous at apex; beneath: the palpi and thorax brownish grey, abdomen pale brown. Upperside: slightly paler brown. Forewing: the cell and apex darker; a white spot similar to that in the male
The Missing Shade of Blue he later says, "this instance is so singular, that it is scarcely worth our observing" he cannot be referring to this particular example, but rather to the "type" of exception that it represents. It is also said that when Hume says, "Let all the different shades of that colour, except that single one, be placed before him, descending gradually from the deepest to the lightest; it is plain that he will perceive a blank, where that shade is wanting", he is assuming that colours are composed of a set of distinct independent hues, when in reality they form a continuum.