diff --git a/boost/graph/directed_graph.hpp b/boost/graph/directed_graph.hpp
index 2c56a4e..b86d87c 100644
--- a/boost/graph/directed_graph.hpp
+++ b/boost/graph/directed_graph.hpp
@@ -92,7 +92,7 @@ public:
     { }
 
     directed_graph(directed_graph const& x)
-        : m_graph(x), m_num_vertices(x.m_num_vertices), m_num_edges(x.m_num_edges)
+        : m_graph(x.m_graph), m_num_vertices(x.m_num_vertices), m_num_edges(x.m_num_edges)
         , m_max_vertex_index(x.m_max_vertex_index), m_max_edge_index(x.m_max_edge_index)
     { }