attempt to draw the attention of man or dog from her nest. Ten years ago last May I came suddenly upon a sitting Lapwing. She rose hurriedly from her nest, and tumbled along the ground, as if she could neither fly nor run.[1] Am I to suppose that she had temporarily lost her power of flight owing to cramp through sitting long in one position, or that her behaviour was merely an expression of anxiety, or did she indeed wish to distract my attention from the whereabouts of her nest? What, may I ask, causes Ducks to leave their young, and to flap along the water in front of an intruder?—W. Storrs Fox (St. Anselm's, Bakewell, Derbyshire).
INSECTA.
The Stridulation of Orthoptera.—I have read with much interest Mr. Aplin's note in 'The Zoologist' for September (p. 432) and, at least as far as Orthoptera are concerned, I can fully corroborate his account of the ventriloquial powers of these insects. Of the three groups of the stridulating Orthoptera, the first is the section called Acridiodea, which produces a buzzing sound by the friction of the posterior femora, which are finely serrated inside (vide Darwin, 'Descent of Man,' 2nd ed. p. 286, fig. 14), against the elytra. As the arrangement of the veins of that part of the elytra affected varies with the species, so does the intensity of the sound. It is a useful accomplishment, and to be able to determine the insect by its stridulation without seeing the performer is not very difficult.
In the Locustodea the sound is produced very differently, namely, by the friction of the basal part of the left elytron over the same part of the right, these parts being modified for the purpose. The stridulation thus produced is very shrill and hard to locate. I have often stalked down our large Locusta viridissima, L., and have usually found it on a bed of nettles or thistles, in the middle of a corn-field, or in stubble, invariably much farther away than I at first expected. The sound appears to come from almost beneath one's feet, but on walking straight towards it, seems to recede into the distance, until it suddenly strikes the ear, very harshly and shrilly at close quarters. As soon as the would-be capturer approaches, the sound ceases, and the insect remains invisible. The assimilation of the green colour of the insect and the green surroundings which it always chooses as a band-stand is so close, that it is almost impossible to detect the creature until it recommences to chirp, when the rapid movement of the elytra betrays its whereabouts. The stridulation of this species is loud and prolonged, but in several of its relatives is short and sharp, and all the more difficult to locate, as the observer does not obtain a fair chance to listen attentively. Such is the case with Platycleis grisea, Fabr., common on the chalky cliffs
- ↑ Vide ante, p. 504.—Ed.
