diff --git a/.travis.yml b/.travis.yml
index 5eb3cb9..5c65a91 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -258,7 +258,6 @@ matrix:
         apt:
           packages:
             - clang-4.0
-            - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-4.0
@@ -270,6 +269,7 @@ matrix:
         apt:
           packages:
             - clang-4.0
+            - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-4.0
@@ -281,7 +281,6 @@ matrix:
         apt:
           packages:
             - clang-5.0
-            - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-5.0
@@ -293,6 +292,7 @@ matrix:
         apt:
           packages:
             - clang-5.0
+            - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
             - llvm-toolchain-trusty-5.0