Open main menu

Page:Popular Science Monthly Volume 65.djvu/432

This page has been proofread, but needs to be validated.
428
POPULAR SCIENCE MONTHLY.

of the six slender hairs or to alight on the triangular area on either lobe which is bounded by the three hairs, the lobes of the trap immediately begin to close together. In perhaps as short a time as five seconds they have shut on the luckless insect, the stout marginal hairs have formed an interlocking fringe about the edge of the trap, preventing its escape, and the small hairs have begun to pour out digestive juices upon the hitherto dry surfaces of the lobes. Any touch, pressure

PSM V65 D432 Venus fly trap.png

Fig. 11. The Venus Fly-trap.

or wound on the slender hairs or on the triangular areas will cause the lobes to close, whether the touch be that of an insect or that of an inanimate object. The other portions of the trap are so much less sensitive that it is necessary for them to he some time in contact with a nitrogenous substance in order to bring about closing of the trap. The contact of raindrops on any part of the leaf is without effect, and the other parts of the plant are entirely without sensibility. Still more effectually is the entrapped insect surrounded with the digestive juices than in the sun-dew, hut the complete consumption of its soft parts may take many days. On reopening after a capture the trap will he torpid and unresponsive for some time, hut if it has chanced to close