wow thats a great camera! the picture is of a female. that last visible "segment" is not really a true segment i dont think, it will get covered up by the second to last visible segment (the one with the tiny little "notch" at the tip but no "spike") after a couple of moults. i have no idea why, maybe that last visible "segment" in your picture somehow becomes an internal part of the genitals? i dont know.
here is another picture of a female of your age (i think):
eventually the last (6th) segment you see will be the big one in the middle of the photo (if that make sense?). here is a picture of a female at fourth instar, you can see now the segment has basically grown over the little one you can see in your picture, and the *** is now alot clearer.
here is what males look like at the same age as your photo:
and at fourht instar:
as you can see the males have one last little spike (where the females have only a little notch). hope this helps.