diff --git a/.circleci/config.yml b/.circleci/config.yml
index c15eb1746..df181f058 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -285,7 +285,7 @@ jobs:
       # this reporter on Python 3.  So drop that and just specify the
       # reporter.
       TAHOE_LAFS_TRIAL_ARGS: "--reporter=subunitv2-file"
-      TAHOE_LAFS_TOX_ENVIRONMENT: "py36"
+      TAHOE_LAFS_TOX_ENVIRONMENT: "py36-coverage"
 
 
   ubuntu-20.04: