516 THE ZOOLOGIST. 



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.* 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. Stores 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, ■ Desceut of Man,' 2nd ed. p. 286, 

 fig. 14), agaiust 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. 



