Cannot read property '_id' of undefined Node JS

I'm trying to make this work fine, but when i send a delete request it says Cannot read property '_id' of undefined, i dont know why its doesnt work, since i have another identical endpont working fine.

    $http.get('/api/equipamentos').success(function(equipamentos) {
  $scope.equipamentos = equipamentos;
  socket.syncUpdates('equipamento', $scope.equipamentos);
});


$scope.addEquipamento = function() {   
  if($scope.equipamento === '') {
    return;
  }

 $http.post('/api/equipamentos', { name: $scope.equipamento });
   $scope.equipamento = '';
};

$scope.deleteEquipamento = function(equipamentos) {
  $http.delete('/api/equipamentos/' + equipamentos._id);
};  

$scope.$on('$destroy', function () {
  socket.unsyncUpdates('equipamento');


});