The correct answer is option 4: The States were compelled to enter the Federation.

Option 1: Provincial Autonomy came into existence. This statement is correct. The Government of India Act, 1935 introduced provincial autonomy, which granted power and autonomy to the provinces in certain matters.

Option 2: Bicameral legislatures were provided in six provinces. This statement is correct. The Act provided for the establishment of bicameral legislatures in six provinces, which consisted of the Legislative Assembly and the Legislative Council.

Option 3: The principles of communal electorates and weightages were further extended. This statement is correct. The Act further extended the provision of separate electorates for different religious communities and the allocation of weightage or reserved seats for minorities.

Option 4: The States were compelled to enter the Federation. This statement is incorrect. The Government of India Act, 1935 did not compel the states to enter the federation. Instead, it provided for the establishment of a federation at the center but allowed the princely states to decide whether to join or not.

Therefore, option 4 is the not correct statement among the given options.