INSTINCTIVE, EMOTIONAL AND REFLEX ACTION 34? 



round the margin of the leaf are long, those in the middle 

 are short. The glands secrete a quantity of a glistening 

 and very sticky substance, which insects mistake for dew 

 or honey and are attracted. Now if the short central ten- 

 tacles are stimulated, all the long peripheral tentacles 

 bend over so that their enlarged ends cover the middle of 

 the leaf. If an individual long tentacle is stimulated, only 

 that particlar tentacle moves. 



"Let us see what happens when an insect touches any 

 of the tentacles of the leaf. If it touches the central ten- 

 tacles, it is held by the sticky substance, and all the long 

 peripheral tentacles bend over and enclose it. If it 

 touches one of the long peripheral tentacles, it is alsc 

 held fast by the sticky secretion, and the tentacle bends 

 over and deposits it on the centre of the leaf. This stim- 

 ulates the short central tentacles, and so all the other 

 large tentacles bend over and enclose the victim. When 

 the prey is thus secured, the glands proceed to secrete a 

 ferment that digests the insect, and the products are 

 absorbed by the leaf. 



"In Scorpirurus the pod containing the seed in some 

 species closely resembles a caterpillar, with the result 

 that insectivorous birds are tempted to seize it. They 

 probably carry it some distance before discovering the 

 mistake, and thus distribute the seeds. In Acanthorhiza 

 adventitious roots provide a thorny palisade above the 

 ground at some distance from the tree, thus preventing 

 the approach of animals. The extraordinary instincts 

 observed among insects have been brought forward in 

 support of the theory that acquired characters are trans- 

 mitted. The instincts of Ammophila and Sphex, two 

 genera of fossorial wasps, have been given as particular 

 cases. The larvae of Ammophila feed upon caterpillars, 

 those of Sphex upon crickets and grasshoppers which are 



