Such insects may be suggested by shape; by colour; by carriage; by shape and colour; by action; by action and shape; by carriage and shape; by action and colour, by action, shape andc olour; or by carraige, shape and colour. The shape cannot be precise because of the hook, and because of the action of the water on feathers, and because, in the case of a floating fly, of the reflective operation of the light passing from air into water.