THE FIELD-CRICKET 127 



The right wing-cover overlaps the left and almost com- 

 pletely covers it, except for the sudden fold which encases 

 the insect's flank. This arrangement is the reverse of 

 that exhibited by the green grasshopper, the Decticus, 

 the Ephippigera, and their relations. The Cricket is 

 right-handed, the others left-handed. The two wing- 

 covers have the same structure. To know one is to 

 know the other. Let us examine that on the right 

 hand. 



It is almost flat on the back, but suddenly folds over at 

 the side, the turn being almost at right angles. This 

 lateral fold encloses the flank of the abdomen and is 

 covered with fine oblique and parallel nervures. The 

 powerful nervures of the dorsal portion of the wing-cover 

 are of the deepest black, and their general eflfect is that 

 of a complicated design, not unlike a tangle of Arabic 

 caligraphy. 



Seen by transmitted light the wing-cover is of a very 

 pale reddish colour, excepting two large adjacent spaces, 

 one of which, the larger and anterior, is triangular in 

 shape, while the other, the smaller and posterior, is oval. 

 Each space is surrounded by a strong nervure and goffered 

 by slight wrinkles or depressions. These two spaces re- 

 present the mirror of the locust tribe ; they constitute the 

 sonorous area. The substance of the wing-cover is finer 

 here than elsewhere, and shows traces of iridescent though 

 somewhat smoky colour. 



These are parts of an admirable instrument, greatly su- 

 perior to that of the Decticus. The five hundred prisms of 

 the bow biting upon the ridges of the wing-cover opposed 

 to it set all four tympanums vibrating at once ; the lower 

 pair by direct friction, the upper pair by the vibration of 



