2i8 THE COURTSHIP OF ANIMALS 



In the details both of position and structure a wonderful 

 variety will be discovered when all the known types are 

 surveyed, and it is possible that they perform different 

 functions in different groups. 



The Locusts and Grasshoppers are among the finest 

 performers of these " harpists," and it would seem that 

 in this group, at any rate, the music they make is of an 

 erotic character. In one of our native Grasshoppers 

 {Stenobothrus melanopterus) these high-pitched and 

 somewhat strident notes are produced by rubbing the 

 roughened inner surface of the hindmost thigh, which 

 forms the base of the great leaping leg, against one of thf 

 libs of the wing-case which is specially enlarged and has 

 a sharp edge. Thereby the wing is thrown into a state of 

 vibration and the musical sound produced. The roughen- 

 ing of the inner surface of the thigh just referred to is pro- 

 duced by a row of bead-like projections whose appearance 

 under the microscope is depicted in the adjoining illustra- 

 tion. This apparatus is well developed in the males, and 

 but feebly, or not at all, in the females. That the music 

 it produces is appreciated by the performers and their 

 mates there can be no doubt, for they are provided with 

 a special apparatus which fulfils the purpose of an ear. 

 In the short-horned Grasshoppers {Acridiidce) this is 

 placed in the middle of the body just above the base 

 of the great thigh. It differs in the details of its 

 construction. In some cases it is formed by a delicate 

 sheet of membrane surrounded by a rim, in others the 

 membrane may be slightly depressed, and in some very 

 much so, the rim closing up to form a broad slit. Such 

 ears, it is to be noted, exist in both sexes, while the 

 stridulating organs do not. That such sound-producing 

 organs serve as stimulants to the sexual passions of the 



