diff --git a/websocket/_abnf.py b/websocket/_abnf.py
index 1b2b855..9242337 100644
--- a/websocket/_abnf.py
+++ b/websocket/_abnf.py
@@ -110,7 +110,7 @@ class ABNF(object):
             raise WebSocketProtocolException("rsv is not implemented, yet")
 
         if self.opcode not in ABNF.OPCODES:
-            raise WebSocketProtocolException("Invalid opcode " + str(self.opcode))
+            raise WebSocketProtocolException("Invalid opcode %r", self.opcode)
 
         if self.opcode == ABNF.OPCODE_PING and not self.fin:
             raise WebSocketProtocolException("Invalid ping frame.")
@@ -284,4 +284,4 @@ class FrameBuffer(object):
         return self.mask is None
 
     def recv_mask(self, recv_fn):
-        self.mask = recv_fn(4) if self.has_mask() else ""
\ No newline at end of file
+        self.mask = recv_fn(4) if self.has_mask() else ""
diff --git a/websocket/_http.py b/websocket/_http.py
index 6cba5e7..1cf5f1a 100644
--- a/websocket/_http.py
+++ b/websocket/_http.py
@@ -154,7 +154,7 @@ def _tunnel(sock, host, port, auth):
 
     if status != 200:
         raise WebSocketProxyException(
-            "failed CONNECT via proxy status: " + str(status))
+            "failed CONNECT via proxy status: %r" + status)
 
 
 def read_headers(sock):