Twenty-three species of longhorn-beetles are recorded from the Solomon Islands, most of them resulting new for the recorded localities. Acalolepta mixta (Hope, 1841) and Jothocera tomentosa (Buquet, 1859) are new for the Solomons.

Pelargoderus stellatus nov. sp. is described.

Dihammus lessoni sericeiceps Kriesche, 1936 is considered as a separated species from the typical form, as follows: Acalolepta sericeiceps (Kriesche, 1936) nov. status.
Dihammus blairi Breuning, 1935 (male) is considered as an older synonym of Dihammus salomonum Breuning, 1938 (female) nov. syn.
Dihammus griseofumatus Gressitt, 1952: 48 (female) is considered as an older synonym of Dihammus trigonus Gressitt, 1952: 50 (male) nov. syn.
Monochamus acanthias Pascoe, 1875 is considered as an older synonym of Dihammus fasciatus aurivarius Gressitt, 1952 nov. syn.

The subspecies Periaptodes frater salomonum Kriesche, 1936 nov. syn. is considered as a synonym of the typical form.

Batocera una White, 1858 is considered an older synonym of B. porioni Rigout, 1987 nov. syn.

The male of Pterolophia (Ale) biplagiaticollis Breuning, 1961 is described.

Keys to the Solomon species of the genera Pterolophia, Prosoplus and Acalolepta are provided.

(in English with Italian summary)

Additional notes
This paper is mainly based on the field research done by Carlo Arrigo Casadio in the Solomon Islands during several travels in Vangunu, Guadalcanal, Malaita, Makira, Bellona and Owaraha between 1998 and 1999.
A photographic reportage about such travels has been presented by Carlo Arrigo Casadio to the Municipality of Casola Valsenio (Ravenna).