Hypocaccus ainu Lewis, 1899: 24 [Japan: Yezo, Ishikari river]; Reichardt, 1941: 308, 322.
Hypocaccus (? Hypocaccus) ainu: Kryzhanovskij and Reichardt, 1976: 229.
Japanese name: Ainu-hamabe-emma-mushi.
Original description. "Oval, convex, coppery black, shining; the head, clypeus rugose, frontal carina strong and angulate on either side, upper surface somewhat obscurely and very irregularly rugose, the rugosities are confined to the anterior half; the thorax is densely punctured at the sides, with a broad band of punctures along the base and a narrow one behind the neck, disk feebly punctulate, marginal stria angulate at a fovea behind the eye and straight behind the neck; the elytra, outer subhumeral stria is wanting, inner short and dimidiate with an appendage split at both ends, striae 1-3 nearly equal and reaching the middle, 4 as long as the third and joining the sutural at the base, the sutural stria is not continued along the apex; the propygidium is densely punctured; the pygidium is somewhat similarly pointed, but except at the apex it is transversely rugose; the prosternum is markedly widened triangularly at the base and the striae gradually meet anteriorly; the mesosternum is margined anteriorly, with a transverse crenulate stria at the base; the anterior tibiae 4-dentate."