diff --git a/python/obitools3/dms/taxo/taxo.pyx b/python/obitools3/dms/taxo/taxo.pyx
index d473d91..314f49f 100755
--- a/python/obitools3/dms/taxo/taxo.pyx
+++ b/python/obitools3/dms/taxo/taxo.pyx
@@ -325,8 +325,9 @@ cdef class Taxonomy(OBIWrapper) :
         cdef Taxon taxon
         try:
             taxon = self.get_taxon_by_taxid(taxid)
-        except:
-            raise StopIteration
+        except Exception as e:
+            print('\n'+e, file=sys.stderr)
+            return 
         if taxon is not None:
             while taxon.taxid != 1:
                 yield taxon
@@ -334,7 +335,7 @@ cdef class Taxonomy(OBIWrapper) :
                 taxon = taxon.parent
             yield taxon
         else:
-            raise StopIteration
+            return
 
 
     def is_ancestor(self, int ancestor_taxid, int taxid):