\[x^{2}y^{5} - y^{5} - x^{2}y^{3} + y^{3} =\]
\[= y^{5}\left( x^{2} - 1 \right) - y^{3}\left( x^{2} - 1 \right) =\]
\[= \left( x^{2} - 1 \right)\left( y^{5} - y^{3} \right) =\]
\[= y^{3}(x - 1)(x + 1)\left( y^{2} - 1 \right) =\]