Unveiling <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si361.svg" display="inline" id="d1e4871"> <mml:mi>δ</mml:mi> </mml:math> Scuti and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si392.svg" display="inline" id="d1e4876"> <mml:mi>γ</mml:mi> </mml:math> Doradus hybrid pulsation of HD 53166 and HD 53349 plus rich frequencies in HD 52788