Published online by Cambridge University Press: 10 July 2009
Adult female reddish or brownish ochreous with a dark marginal zone, to uniform dark castaneous. Broadly oval to sub circular; flat; margin evenly rounded, without trace of stigmatic clefts (fig. 1, a). Anal cleft completely fused, its position marked by a slight ridge and thickening of the derm. Anal operculum approximately central, the distance from posterior margin of body to anterior extremity of operculum being equivalent to nine-twentieths of the total length. Valves of operculum (fig. 1, d) elongate; basal edge nearly twice as long as outer edge; inner edge more than twice the length of the outer edge. Antenna (fig. 1, c) 7-jointed: formula, 3,7, (2, 4), 5, 6, or (3, 4, 7), 2, 5, 6. In some examples there are traces of a division in the third joint.