diff --git a/imagekit/registry.py b/imagekit/registry.py
index 6ff9210..8d082cd 100644
--- a/imagekit/registry.py
+++ b/imagekit/registry.py
@@ -103,7 +103,7 @@ class SourceGroupRegistry(object):
             return
 
         for spec in (generator_registry.get(id, source=source, **info)
-                     for id in self._sources_groups[source_group]):
+                     for id in self._source_groups[source_group]):
             event_name = {
                 source_created: 'source_created',
                 source_changed: 'source_changed',