diff --git a/spacy/munge/read_conll.py b/spacy/munge/read_conll.py
index e18fb7557..ed6037a4d 100644
--- a/spacy/munge/read_conll.py
+++ b/spacy/munge/read_conll.py
@@ -13,7 +13,6 @@ def parse(sent_text, strip_bad_periods=False):
     id_map = {}
     for i, line in enumerate(sent_text.split('\n')):
         word, tag, head, dep = _parse_line(line)
-        id_map[i] = len(words)
         if strip_bad_periods and words and _is_bad_period(words[-1], word):
             continue
   
@@ -24,8 +23,6 @@ def parse(sent_text, strip_bad_periods=False):
             'head': int(head) - 1,
             'dep': dep})
         words.append(word)
-    for entry in annot:
-        entry['head'] = id_map.get(entry['head'], entry['head'])
     return words, annot