Normally Rosemary beetles (Chrysolina americana) [1] forage visibly but tucked away between leaves of their host plants; in our garden those are Rosemary (rosmarinus-officinalis) and Lavender (Lavendula angustifolia). Numerous beetles found a spot on the plants. To my surprise the beetles leave their hideouts and appear high on the flowerstalks hovering above the plant where they feed on leaves and sometimes on the stalk.

Literature
1 Nederlands Soortenregister