diff --git a/capa/features/extractors/helpers.py b/capa/features/extractors/helpers.py
index f6d91333b..24eee27bd 100644
--- a/capa/features/extractors/helpers.py
+++ b/capa/features/extractors/helpers.py
@@ -52,6 +52,9 @@ def generate_symbols(dll: str, symbol: str) -> Iterator[str]:
       - CreateFileA
       - CreateFile
     """
+    # normalize dll name
+    dll = dll.lower()
+
     # kernel32.CreateFileA
     yield "%s.%s" % (dll, symbol)
 
diff --git a/capa/features/insn.py b/capa/features/insn.py
index 85ef9a399..4843d95c4 100644
--- a/capa/features/insn.py
+++ b/capa/features/insn.py
@@ -12,11 +12,6 @@
 
 class API(Feature):
     def __init__(self, name: str, description=None):
-        # Downcase library name if given
-        if "." in name:
-            modname, _, impname = name.rpartition(".")
-            name = modname.lower() + "." + impname
-
         super(API, self).__init__(name, description=description)