Maltawildplants.com is now considered an online flora of the Maltese islands, portraying more than 900 species of plants found in Maltese habitats. It harbours a forum created in 2005 were memberes discuss topics about the Maltese flora and ID of plants.
Found this on an Euphorbia pinea plant. Beautiful and large caterpillar. After some research, it seems to be a caterpillar of the species Hyles sammuti which according to a local book should be a recently described Maltese species dedicated to a Maltese expert on the field. But obviously this might be a misidentification as always
When I was young I remember there used to be plenty of nice caterpillars (that's my best description of them ) at Birzebbugia Valley (behind Pretty Bay) but now that area has been completely built over. One day must visit to see what's left.