An Array does not have a constructor, when you create an array you are creating a list or collection of objects, it is the objects that make up the array that will have the constructor, for example.
var b = new byte[8];
will create an array of 8 objects of type byte
where each element of the array will be null, using constructor notation is invalid but you can use the initializer notation, eg.
var b = new byte[8] { new byte(), new byte(), ... };
Using this notation will initialize the array of 8 elements of type byte
to a new instance of byte
In short var b = new byte()
is a instantiating a variable as a byte
and calling the constructor of the object, var b = new byte[8]
is creating an array of n elements of type byte
each initialized to null.
I hope that helps