diff --git a/.travis.yml b/.travis.yml
index 31348f066..a7b03d20a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,7 +20,7 @@ env:
 install: "travis_retry pip install tox coveralls"
 before_script: '[ "${TOXENV:0:2}" != "py" ] || ./tests/boulder-start.sh'
 # TODO: eliminate substring slice bashism
-script: 'travis_retry tox && ([ "${TOXENV:0:2}" != "py" ] || (source tox.venv/bin/activate && ./tests/boulder-integration.sh))'
+script: 'travis_retry tox && ([ "${TOXENV:0:2}" != "py" ] || (source .tox/$TOXENV/bin/activate && ./tests/boulder-integration.sh))'
 
 after_success: '[ "$TOXENV" == "cover" ] && coveralls'
 
diff --git a/tox.ini b/tox.ini
index 7d5027bf8..9d5ccf49c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,10 +9,6 @@ skipsdist = true
 envlist = py26,py27,py34,cover,lint
 
 [testenv]
-# share one venv across testenvs, instead of multiple
-# .tox/{py26,py27,cover,lint}; but do NOT set envdir to
-# {toxinidir}/venv as it will destroy existing dev venv
-envdir = {toxinidir}/tox.venv
 commands =
     pip install -r requirements.txt -e acme -e .[testing] -e letsencrypt-apache -e letsencrypt-nginx
     # -q does not suppress errors
@@ -27,7 +23,6 @@ setenv =
 # https://testrun.org/tox/latest/example/basic.html#special-handling-of-pythonhas
 
 [testenv:py34]
-envdir = {toxinidir}/tox.venv3
 commands =
     pip install -e acme[testing]
     nosetests acme/acme