STRIDULATING ORGANS AND THE EAR. 



77 



way belong to the genus Stenobothrus.'' Fig, 44 shows the 

 teeth on the inside of the femur of the hind leg, which are 

 scraped against the veins of the tegmina. An enlarged view 



lfe^i!^Sgi& 



Fig.44. — Hind leg of Stenobothriis; s, ridge with teeth, 

 greatly enlarged. After Landois. 



Ridge and teeth 



of these teeth is also given. According to Scudder, the 

 Stenohothri, when about to stridulate, place themselves in a 

 nearly horizontal position, with the head a little elevated; 

 then they raise both hind legs at once, and grating the 

 femora against the outer surface of the tegima, produce 

 notes which in the different species vary in rapidit}^, number 

 and duration. The first one or two movements are frequent- 

 ly noiseless or faint; and when the sky is overcast, the 

 movements are less rapid. Prof. Scudder has recorded the 

 songs of several species by means of a musical notation. 

 The species of locusts that belong to the family of CEdipo- 

 dinge produce sounds by rubbing together the upper surface 

 of the front edge of the wings and the under surface of the 

 wing-covers. Such insects produce sounds only while on the 

 wing. When w^e watch the common large bright-colored 

 locust that is so abundant during the summer upon roads 

 and sandy spots and that often remains stationary while 

 on the wing, we can see that the wing-covers are held almost 

 motionless in a perpendicular position, while the large and 

 fan-like lower wings are fully expanded, and are rapidly 

 moved up and down. The longitudinal veins of the lower 

 wings are well developed, and as the anterior vein strikes 

 the upper wing while flying, a rattling sound is produced. 

 In some cases both sexes can make such sounds. Landois 



