We investigated shear-induced structures for a semidilute solution of ultrahigh molecular weight polyethylene (UHMWPE) with a paraffin wax as a solvent by means of shear small-angle light scattering, shear microscopy, birefringence, and rheology. The solution has a reduced concentration (c/c* where c and c* is concentration and the overlap concentration, respectively) of 11 and hence well-developed entanglements. The structures were investigated at temperature of 124 degrees C, which is approximately equal to the equilibrium melting temperature of crystals in the solution at quiescent state. We found both shear-induced liquid-liquid phase separation and shear-induced crystallization, when the solution was subjected to shear flow at shear rate larger than the critical shear rate gamma(c,streak). Time change in the shear-induced structures after onset of the shear at gamma > gamma(c,streak) or after cessation of the same shear illuminated that the shear-induced phase separation triggers the shear-induced crystallization into fibrous structures: crystallization occurs through regions rich in polymer concentration that are built up by the shear.