CHAPTEE XI. 



STERNOXr, OR SKIPJACK BEETLES. 



T. USE the word which is placed at the head of this chapter 

 because it is a more appropriate name than that which is some- 

 times given to this tribe of Beetles ; namely, Serricornes, or 

 " saw-horned." Many Beetles might be termed Serricornes, but 

 the name of Sternoxi, or "sharp-breasted," is exj)ressive of a 

 characteristic peculiar to this tribe. The Sternoxi have the 

 sternum, or under part of the thorax, prolonged into a sharp, 

 spike-like appendage, which fits into a corresponding hollow 

 between the bases of the middle pair of legs. This structure 

 can be easily seen by taking any of our common Skipjack or 

 Click Beetles and examining it with a lens. 



While so doing the observer will probably find that the insect 

 will bend back the thorax, and then, with a smart jerk and a 

 clicking sound, fling it forward. If at the time the Beetle be 

 lying on its back, it will spring high into the air, and in most 

 cases fall on its feet, this being evidently the object for which 

 the structure of the thorax was intended, the legs being in many 

 species so short, that if the insect falls on its back on a smooth 

 surface it can scarcely ever regain its feet. 



Perhaps the reader may ask why the Beetle should be so 

 mucli in the habit of falling on its back that a special provision 

 should be made to enable it to get upon its feet ? The reason is, 

 that whenever the insect is alarmed it always loosens its hold of 

 any object to which it may be clinging, and falls to the ground, 

 where it lies motionless as a stone, until the danger, real or 

 imaginary, has passed away. Now, if it should happen to fall 

 on a smooth instead of a rough surface, it would lie there until 

 it died, the legs being so short that they could not touch the 

 ground. The power of springing into the air, liowever, com- 



