Another especially interesting night-flyer is the ghost moth. Just as the twilight of a summer evening is deepening into darkness, and a soft, warm wind stirs the foliage of the woods, the ghost moth comes abroad. The observer sees a fitful apparition which suddenly vanishes into space. First a large insect with long wings is seen advancing, it comes straight on, then flutters in the air--and is gone. Whilst endeavouring to discover the mysterious retreat of the moth, it will suddenly reappear, and even whilst the eye closely follows its flight, will again vanish. This effect is produced by the different colour of the wings on their upper and lower sides. Above they are snowy white, and consequently visible even in the deep twilight; but on the under side they, as well as the whole body, are of a deep dusky brown so that when that side is suddenly turned towards the spectator it becomes invisible. As the male flies in the night, the white shining upper surface of the wings glitters curiously, almost appearing as if they were giving out their own light. Standing in one of the rides of a woodland glade just as day is departing, one is pierced, thrilled by a perfect storm of song. This loud swelling volume of sound softens as the darkness deepens, and then only the polyglot wood-thrush is heard. The stem of the silver birch has ceased to vibrate to the blackbird's whistle, and as darkness comes a new set of sounds take possession of the night. But passing down through the meadows we have other thoughts than listening to these. Another night singer is the blackcap. The flute-like mellowness and wild sweetness of its song give it a high place among British warblers--next only to the nightingale. The blackcap has neither the fulness nor the force, but it has all and more of the former's purity. This little hideling, with its timid obtrusiveness, never strays far from cultivation. One provision it requires, and this is seclusion. Its shy and retiring habits teach it to search out dense retreats, and it is rarely seen. If observed on the confines of its corral of boughs it immediately begins to perform a series of evolutions until it has placed a dense screen of brushwood between itself and the observer.