Genus Amblopusa Casey, 1894

[Japanese name: Nokoba-umi-hanekakushi-zoku]

Amblopusa Casey, 1894: 355 (original description; type species: A. brevipes Casey, 1894); Ahn & Ashe, 1995: 138 (redescription; key to species).

Boreohadinus Sawada, 1991: 147 (original description; type species: B. pacifica Sawada, 1991).

Diagnosis. This genus is similar to Halorhadinus in body shape but can be distinguished by the following characteristics: hind wings usually absent; female spermatheca not coiled or coiled one time (Figs. 18B, D & F); mandible slightly longer than wide (Fig. 19E); labrum transverse (Fig. 19A); one medial seta presents on prementum (Fig. 19C) (modified after Sawada, 1991). From other genera of Liparocephalini, this genus can be easily distinguished by the combination of the following characteristics: body slender; abdominal segments III–VII almost parallel-sided (Fig. 17); labial palpus 2-segmented, ligula reaching to 1/2 of segment I of labial palpus (Fig. 19C).

Habitat. All species of this genus have been collected from gravel beaches (Figs. 26B & C).

Distribution. Japan: Hokkaidô; Russia (Kuril Islands); Canada; USA.