The discussion of the motion of single particles in stellarators is simplified by identifying three distinct groups of particles. The drift equations are used to treat these groups by analytical and numerical methods. It is shown that, unlike an axisymmetric system the region of a stellarator with surfaces closed about a magnetic axis need not form a perfect trap. In fact, unless the toroidal curvature is very small, particles in one of the groups, those mirrored between maxima in a single period of the helical field, will drift out beyond the separatrix no matter how large the magnetic field strength.