Ponana punctipennis.
Size: approx. 5-7 mm. Photo: 06/12/12, 10 pm.

Ponana punctipennis has spot-like markings all over, which distinguishes it from P. rubida
bug guide (this photo):

Ponana rubida (Leafhopper (nonspecific)).
Size: approx. 5 mm. Photo: 09/05/11, 11 pm.

This leafhopper is Ponana rubida. It came to the light of our living room window. The genus has 27 species in North America. The species P. rubida has very few markings. 

bug guide:

Ponana puncticollis.
Photo: 07/02/12, 11 pm.

Originally I thought this is another specimen of P. rubia but an expert identified it now as P. puncticollis. The word 'puncticollis' means 'spot-necked' and the typical length of these leafhoppers is 6-8 mm. 

bug guide (this photo):

Ponana sp..
Photo: 09/03/14, 8 pm.

This is a green specimen of the genus Ponana but really doesn't match up well with the reported species. 
bug guide (this photo):