i think first one male,second female... why? because the lenght of the tail from the first garter is a little bigger i think,and the base of the tail (by the cloaca) is a little thicker...
(i hope my english is good enough to understand :-) )
I might agree with Kuno...At the first picture, it almost looks like you can see some bulging (hemi-penisses). The second ones tail is much shorter (may be the picture...) and it narrows down quite quickly.
Although, some sharper pictures would be a great help!
what ssp by the way?
I was looking at one of the snakes in question resting and it appeared as though the base of its tail was wider than usual. And the tail is short, so I'm gonna say male.