An examination has been made of factors triggering attack behaviour in adultCephalota circumdata leonschaeferi(Cassola), living in the coastal strip of the Orbetello Lagoon Nature Reserve. Coloured dummies (blue, white, brown, black, red, and green) of various sizes (3.8, 7.5, 15 and 30 mm) have been used to evaluate the rôle of the following stimuli: movement, size and colour. Attacks recorded with experiments carried out in absence of movement (3.83%) were markedly fewer than those in presence (57.26%) of movement. The size of bait most frequently attacked by Tiger beetles was the 7.5-mm long one (corresponding to 1/2 the size of the adultCephalota). The largest bait (30 mm) was significantly less stimulating than the other three sizes. Red was the colour that most stimulated attack and white the least. Brown and black gave results more similar to those of red, whereas green and blue frequently displayed a significantly less stimulatory effect.