Neophilaenus species can be distinguished as adults from Philaenus spumarius by the more parallel outer edges of the wings when viewed from above (as opposed to the more convex outline of P. spumarius) and their overall pattern of markings. They are much smaller than Aphrophora species. 
 
Neophilaenus campestris is relatively easily identified by the two pale areas on the outer edge of the wings on an otherwise pale brownish background. There is often a slightly  darker mid-line running back from the head.