Amount of walking stick sp. in USA

[BensBeasts1]

I just got a book today Kaufman’s field  guide to North American Insects. When I looked at the Phasmid page (Walkingsticks) I realized that there were alot more species in the US then I originally thought. 
 

Does anyone happen to know the exact number of sp. in the US?

 

[Dynastes]

Chad Arment has a neat book compiling a lot of the old literature for all different ones but it doesn't have the thirty new timema that all look the same.