Stenhomalus japonicus, a species occuring in Russian Far East and Japan, has been described from Sado Island (Niigata Prefecture, Japan) as Obrium japonicum by Maurice Pic in 1904 [❖]. S. japonicus is one of the most taxonomically problematic East Palaearctic species of the Stenhomalini tribe. Taxon was included in the genus Obrium for a long time (followed the original description) and its true systematic position in Stenhomalus genus (Stenhomalini tribe) as the result of reexamination of holotype was published by Tatsuya Niisato in 2006 [✧]. Moreover, the names S. lighti Gressitt, 1935 and S. vulcanus Tsherepanov et Tsherepanova, 1976 were suggested as junior synonyms of this taxon [☆][▾].

S. japonicus is a polyphagous species, its larvae develop in dying twigs of many deciduous trees and shrubs. Larvae feed in bark, then subcortically along shoot, plugging gallery deeply impressed on sapwood with a fine frass. Mature larvae enter the wood at end of gallery (up to 16 cm long), make hook-shaped pupal cell along twig at a depth of 4 - 10 mm and plug inlet with frass. Pupation and hatching during late summer / early autumn, young beetles overwinter in pupal cells. Life-cycle 2 year [▽].

Body length:	4.4 - 9 mm
Life cycle:	2 years
Adults in:	May - August
Host plant:	polyphagous in deciduous shrubs and trees (e.g. Cornus, Sydonia, Phellodendron)
Distribution:	Russian Far East, Japan

The depicted beetle was reared from larva found on Mt. Tachibanayama (Fukuoka City environs, Fukuoka prefecture, Kyushu, Japan) in 1967.

Collected by Takahisa Watanabe