CHAPTER XV. 
THE DEATH-FEIGNING 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 Scarabzeus for example, have 
a precisely contrary effect on species endowed with 
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 (Pholeus) when approached draw 
their feet together in the middle of the web, and spin 
the body round with such velocity as to resemble a 
whirligic. 
Certain mammals and birds also possess the death- 
