How do insects orient themselves when proceeding to a place which is more or less distant? Are they simply reflex machines, as Bethe says? Or are they guided by a special directive sense, as Fabre believed? Or are they not simply served, like all of us, by the ordinary senses and by a memory of places? Here again we are in the open field of controversy.

In the course of an excellent study devoted to this question, Claparède1 observes ' 6 that the most fundamental point which needs elucidation is whether the objective, the spot toward which an animal directs itself, can be a goal unknown to it, one which it has never visited, never explored ; and further, whether or not this goal is directly perceptible (by sight, smell, hearing), and in the latter case, whether the path followed does or does not include landmarks. . . . Each one of these cases, in fact, authorizes a différent hypothesis.

1 Ed. Claparède, La faculté d'orientation lointaine, 1903. (Arch, de psychol, Geneve, v. 2. pp. 132-180).

We see, then, the importance," adds Claparède, "which should be placed upon a preliminary way."

This is absolutely our opinion, and in first considering flying insects we will follow the plan outlined by Claparède.