It's name is Phyllipa in a great honor to a former per that I've. This carnivorous plant is a Venus flytrap (Dionaea muscipula) and with Aldrovanda is one of the only two active snap traps carnivorous plant. (At bottom some info from wikipedia)
Their trapping mechanism is based on their shape and rapid movement. Aldrovanda is aquatic and specialised in catching small invertebrates; Dionaea is terrestrial and catches a variety of arthropods, including spiders.
The traps are very similar, with leaves whose terminal section is divided into two lobes, hinged along the midrib. Trigger hairs (three on each lobe in Dionaea muscipula, many more in the case of Aldrovanda) inside the trap lobes are sensitive to touch. When a trigger hair is bent, stretch-gated ion channels in the membranes of cells at the base of the trigger hair open, generating an action potential that propagates to cells in the midrib. These cells respond by pumping out ions, which may either cause water to follow by osmosis (collapsing the cells in the midrib) or cause rapid acid growth. The mechanism is still debated, but in any case, changes in the shape of cells in the midrib allow the lobes, held under tension, to snap shut, flipping rapidly from convex to concave and interring the prey. This whole process takes less than a second. In the Venus flytrap, closure in response to raindrops and blown-in debris is prevented by the leaves having a simple memory: for the lobes to shut, two stimuli are required, 0.5 to 30 seconds apart.
The snapping of the leaves is a case of thigmonasty (undirected movement in response to touch). Further stimulation of the lobe's internal surfaces by the struggling insects causes the lobes to close even tighter (thigmotropism), sealing the lobes hermetically and forming a stomach in which digestion occurs over a period of one to two weeks. Leaves can be reused three or four times before they become unresponsive to stimulation, depending on the growing conditions