Maybe PyPy requires lxml 3.6.0?

.travis.yml

@@ -54,7 +54,6 @@ install:
         tar -jxf ${PYPY_VERSION}.tar.bz2
         virtualenv --python="$PYPY_VERSION/bin/pypy3" "$HOME/virtualenvs/$PYPY_VERSION"
         source "$HOME/virtualenvs/$PYPY_VERSION/bin/activate"
-        pip install -U cython  # https://bitbucket.org/pypy/compatibility/wiki/lxml
       fi
   - pip install -U tox twine wheel codecov
 

tox.ini

@@ -58,13 +58,12 @@ deps =
 commands =
     pylint conftest.py docs extras scrapy setup.py tests
 
-[testenv:pinned]
+[pinned-common]
 deps =
     -ctests/constraints.txt
     cryptography==2.0
     cssselect==0.9.1
     itemadapter==0.1.0
-    lxml==3.5.0
     parsel==1.5.0
     Protego==0.1.15
     PyDispatcher==2.0.5
@@ -79,6 +78,11 @@ deps =
     botocore==1.3.23
     Pillow==3.4.2
 
+[testenv:pinned]
+deps =
+    {[pinned-common]deps}
+    lxml==3.5.0
+
 [testenv:extra-deps]
 deps =
     {[testenv]deps}
@@ -101,7 +105,11 @@ commands =
 [testenv:pypy3-pinned]
 basepython = {[testenv:pypy3]basepython}
 commands = {[testenv:pypy3]commands}
-deps = {[testenv:pinned]deps}
+deps =
+    {[pinned-common]deps}
+    # https://github.com/lxml/lxml/pull/187
+    lxml==3.6.0
+
 
 [docs]
 changedir = docs