diff --git a/tox.ini b/tox.ini
index da17f27..767b25a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,13 +12,13 @@ commands = pip install .
         py.test -v
 
 [testenv:circleci_27]
-basepython = 2.7.10
+basepython = python2.7.10
 
 [testenv:circleci_34]
-basepython = 3.4.3
+basepython = python3.4.3
 
 [testenv:circleci_35]
-basepython = 3.5
+basepython = python3.5
 
 [testenv:circleci_pypy]
-basepython = pypy2.5.0
+basepython = pypy-2.5.0