diff --git a/modules/mol/base/src/impl/query_impl.cc b/modules/mol/base/src/impl/query_impl.cc
index 849b2977abcdd2e74ba5907f3258627d0c18320e..618d579a60b6a9bb0a3f9cdd507b3732029a427a 100644
--- a/modules/mol/base/src/impl/query_impl.cc
+++ b/modules/mol/base/src/impl/query_impl.cc
@@ -180,7 +180,8 @@ QueryToken QueryLexer::LexToken() {
     if (isdigit(current_char) || current_char=='-') {
       return this->LexNumericToken();
     }
-    if (isalpha(current_char) || current_char=='?' || current_char=='*') {
+    if (isalpha(current_char) || current_char=='?' || current_char=='*' || 
+        current_char=='_') {
       return this->LexIdentOrStringToken();
     }
     switch (current_char) {