Chlorotettix necopinus.
Photo: 08/18/14, 9 pm.

Chlorotettix necopinus is the only brown member of the genus. It is similar to Athysanus argentarius, but is darker and narrower. I think that the brown band between the eyes makes this one cool looking leafhopper.  

bug guide (these photos):

Chlorotettix sp..
Size: approx. 4 mm. Photo: 04/17/12, 11 pm.

Chlorotettix sp. has at least five species in the US. An expert (see link) states that this genus is "(l)arger than Empoasca, with more definite wing veins". 
bug guide (this photo):