developing that spark of intellect which it possesses in common with all
animal organisms.




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 Scarabseus 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 (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-simulating instinct,