Hemicoelus gibbicollis (Anobiidae) 

the Pacific powder-post beetle, Pacific deathwatch beetle 



Hemicoelus gibbicolis adult

2.5 to 5.5 mm in lrngth with striate elytra covered in short, yellowish hairs.  The thorax is notably narrower than the elytra and when seen from the side, has a distinct lump.

Adults are reddish to dark brown and lay eggs in crevices, small openings, or pores of unfinished wood. It can take 2 years to complete each generation. The species frequently encountered in California is the Pacific deathwatch beetle,  Hemicoelus gibbicollis.








Anobiid larva Larval stage do most of the damage and their galleries is packed with frass. The frass is only visible outside the attacked wood when larvae or adults push it out through emergence holes.



Hemicoelus damage


Along the Pacific coast, from California to Alaska, the Pacific powder-post beetle is the most damaging of the powder-post beetles.  Well-seasoned, unrotted sapwood is attacked, often repeatedly until the wood is pulverized.  Structural timber and subflooring of older buildings lacking basements are most frequently infested. 








Principal Hosts: 

Seasoned wood (wood products and dead trees) of Douglas-fir, Abies, Tsuga heterophylla, Picea, Seqouia, Acer, Alnus, Prunus, Salix and Quercus are attacked. 

Economic Importance: 

Considered by some to be the most serious pest among powder-post beetles, in the broad sense of the term (i.e. the bostricids, anobiids and lyctids). 

References and Links: 

EAG: 536-538; FC: 270.