INSECT VARIETY, 165 



common with the percussional sounds of a child's rattle, or the 

 f rictional notes of scraping cardboard, wood, or metal ; a reason, 

 by the way, why their perceptive organs should widely differ 

 from ours. The strokes of the femora when prolonged are slow, 

 producing more basal notes ; the shorter are always rapid, effect- 

 ing those higher in pitch. They are almost invariably diurnal 

 musicians, and the greater portion are tuneful only in the glow 

 of the sun. The notes of the male, when in the presence of 

 a female, diminish in intensity, or change completely in rhythm. 



Certain males of the larger locust kinds are noticed to 

 produce notes by slightly raising their elytra roof-shaped, and 

 bending the tibia of the hind leg beneath the femora, where 

 they are lodged in the furrows designed to receive them. After 

 this they either draw both legs briskly up and down through a 

 small angle (Plate II., Fig. 3, a b') , or scrape first on one elytron 

 and then on the other, using the right and left thighs alternately. 

 Thus Yersin observes, that when FacJiijtylm nigrofasciatus walks 

 on the sand it keeps the legs somewhat removed from the 

 body ; but that from time to time it raises one or the other, 

 and passes it with considerable play and rapidity over the 

 elytron, bringing forth a brief indistinct note. Another 

 locust [Paracinema hlngnatitm) effects an analogous movement, but 

 employs the legs simultaneously. In these and other species of 

 TachyUjlus the raised keel on the inner side of the groove of the 

 hind legs appears smooth. It is scraped during the to-and-fro 

 action of the hind leg on a vein intercalated between the interno- 

 mediate and exteruomediate, which is bowed out at either side of 

 the roof-shaped elytra. This is minutely serrated to form a lima, 

 here constituting the passive organ of music (Plate II., Fig. 3, x). 

 The wing-covers, over which the resulting vibrations spread and 

 accumulate by the conduction of the veins, are tough, and must 

 be considered as forming a delicate musical box, where the 

 tremors induce and lead sonoral pulses. These poured on the 

 ambient ether produce the feeble trill of the locust. 



Herr Vitis Graber relates of Stetheopliyma grossnm, L., that 

 when a number of individuals of this species were springing 

 around him in the high grass, as they leajit the peculiar noise of 

 the males came forth. This sound resembled most the chirp 

 elicited on closing the elytra of a leaf-cricket ; it v^^as short and 



