This is an interesting postcard printed and sent in the USA in 1915. The description is not correct. The author seems to have mistaken the Braunschweiger hussar for a LeibHussar. Given the mix of different cavalry types maybe this is a cavalry signal school?
Nice postcard and thanks for posting
Here is what I think
They are on manovers
Also since the drawing are a little crude
I think that he is a member of 1 L H R 1
they just did the skull too small and he looks like H R 17
Steve