98 GOUREAU ON THE 



its prey. This little insect leaps with surprising agility by 

 means of its posterior thighs, which are much thickened. This 

 character, and the form of the posterior tarsi, which are com- 

 posed of two parallel pieces, which are without articulation, 

 and each terminated by a small hook, distinguishes X. variegata 

 from the mole-crickets, which in the other parts of the body 

 it closely resembles. The elytra of this little insect appear to 

 be smooth, and present under the magnifying glass two slender 

 longitudinal nervures on the side-cover, and a slight im- 

 pression near the inner border towards their extremity. There 

 is nothing like a musical instrument distinguishable. I am 

 inclined to believe these insects mute, not only because I have 

 never heard them stridulate, but also because I have never 

 seen them make the same movement with their elytra or legs 

 that the crickets, grasshoppers, and locusts do when they wish 

 to produce sounds with their instruments. 



Grasshoppers {Locusta, Latr.) 



The grasshoppers form another family of sound-producing 

 Ortkoptera, whose musical instrument has considerable analogy 

 with that of the crickets. It is placed like theirs at the base 

 of the elytra, and the insects play it by rubbing these organs 

 briskly one on the other. But the two instruments are not 

 symmetrical, and the insect remains mute if he ci'osses them in 

 an unnatural order. The left elytron should be above and the 

 right below. These organs vary in the different genera ; and 

 they even differ slightly in species of the same genus. 

 Amongst the long-winged grasshoppers, the males alone are 

 provided with them, but the females of those with short elytra 

 which compose the genus Ephippiger of Latreille, possess the 

 faculty of song as well as the males. 



The males sing to call the females, and to please them. 

 Three or four are sometimes seen collected together on the 

 branches of the same shrub, where they perform concerts in 

 company, which although they may not seem very harmonious 

 to us, doubtless do so to the grasshoppers themselves. They 

 appear to take great delight in this music, and to emulate 

 each other in singing. In these concerts it has been observed 

 that the musical instruments are not all equally perfect ; that 

 some give out clear and acute sounds, whilst others produce 



