CHAPTER XV. 



THE DEATH-FEIGNJNG INSTINCT. 



Most people are familiar with the phenomenon of 

 " death-feigning," commonly seen in coleopterous 

 insects, and in many spiders. This highly curious 

 instinct is also possessed by some vertebrates. In 

 insects it is probably due to temporary paralysis 

 occasioned by sudden concussion, for when beetles 

 alight abruptly, though voluntarily, they assume that 

 appearance of death, which lasts for a few moments. 

 Some species, indeed, are so highly sensitive that 

 the slightest touch, or even a sudden menace, will 

 instantly throw them into this motionless, death- 

 simulating condition. Curiously enough, the same 

 causes which produce this trance in slow-moving 

 species, like those of Scarabgeus for example, have 

 a precisely contrary efiFect on species endowed Avith 

 great activity. Rapacious beetles, when disturbed, 

 scuttle quickly out of sight, and some water-beetles 

 spin about the surface, in circles or zigzag lines, so 

 rapidly as to confuse the eye. Our common long- 

 legged spiders (Pholcus) when approached draw 

 their feet together in the middle of the web, and spin 

 the body round with such velocity as to resemble a 

 whirligig. 



Certain mammals and birds also possess the death- 



