There are two main methods to attach the bra strap at the back to the wing 'the camisole' and 'the leotard'.
The camisole strap is so called because it has the same attachment used for a camisole. This style of strap has been around and used the longest for lingerie. The straps are sewn at a right angle to the wing at a set point from the hook and eye (usually around 5cm). This style produces a square back shape and can work on all sizes of bras. However when reaching the bigger cup it put a lot stress on the point where it meets the wing, and may cause the wing to pull up especially if the right isn't being worn.
The leotard strap is also know as the 'U' back, unlike the camisole the leotard strap has a round look and lo and behold gains it name from looking similar to a leotard. It's mainly used for the larger cup as the wings need to be wider to support the larger cups. The leotard strap is sewn along the back curve of the wing which means that the weight of the breast is distributed evenly throughout the underband, and takes the weight out of the straps. One of the main problems when designing a bra with the leotard style strap is making the curve shape too wide. If it is too wide then it will cause the straps to fall off the wearer's shoulders.
For those wishing to know more about the components of lingerie. the book "The Anatomy of a Bra" covers each component of the bra in detail.