Description (from preserved specimen).
Length (excluding setae)—Ca., 12 mm.
Head—Large; sub-quadrangular, with slightly convex margins. Ground colour yellow, covered all over with fine sepia stipling, except on three small areas, one exterior to each ocellus. Eyes large, dark brown. Mouthparts of the typical Atalophlebid description. The median bay of the anterior edge of the labrum bears five prominent teeth.
Thorax—Yellow with sepia stipling: wing-pads cover the first two abdominal segments.
Abdomen—Very broad, narrowing considerably posteriorly: latero-posterior angles of segments six to nine project backwards as sharp teeth: the ninth and tenth segments are telescoped, the former, in particular, having a much narrower area visible than is usual in this genus. The ground colour is yellowish; heavy, symmetrical, dark markings, on each side of the median line, are found dorsally on the first nine segments: ventrally, the dark markings are placed in a median area on each of these segments and are suggestive of the same markings in Oniscigaster.
Caudal setae (broken)—Apparently ca. 12 mm.: yellow: whorls of very short, fine hairs occur at the joinings.
Legs—Colour dingy yellowish-brown (but markings possibly washed out by preservative).
The femora and tibiae of the middle pair of legs are somewhat longer than those of the anterior pair, but the tarsi are slightly shorter. The femora and tibiae of the posterior pair are longer than those of the other two pairs, the tarsi being about the same length as in the anterior pair.
There are spines on the surfaces and on the dorsal and ventral edges of all the femora, on the ventral edges of the tibiae (fewer on those of the middle pair of legs), on the dorsal edge of the posterior tibiae only and on the ventral edges of the posterior and anterior tarsi. There are fringes of a few weak hairs on the dorsal edges of the tibiae of the second and third pairs of legs.
The tarsal claws are toothed underneath.
Gills—There is a pair of gills on each of the first seven abdominal segments. The gills become smaller posteriorly. Each gill consists of a pair of ovate-acuminate lamellae. The tracheal venation is pinnate with a stout central trachea. The gills of the last pair are very small and the inner lamella is minute: both have a central trachea but no pinnate branches.