82 MIND IN EVOLUTION CHAP. 



directing a series of actions towards a definite result, that 

 forms the basis of Instinct. The construction of a 

 cocoon by a caterpillar, or a tube by a worm, may be 

 quite mechanical, but there is evidence of something not 

 quite mechanical in the power of repairing the things con- 

 structed, or of dealing with any special obstacle to con- 

 struction in a suitable way. The Ant Lion, according to 

 writers quoted by Romanes, 1 has some capacity of this kind, 

 and even among worms we find traces of adaptation. Thus, 

 the Terebella builds its tube by selecting grains of sand 

 in captivity it is less dainty, but generally rejects glass- 

 seizing them with its feelers, drawing them in, and, after 

 secreting a certain cement upon them, protruding its head 

 and depositing them where required. It not only repairs 

 holes, but if a piece does not stick at first, it repeats the 

 process of cementing, while if the object is too big to be 

 drawn in, it protrudes its forepart to the entrance of the 

 tube, and cements it on the spot. 2 Caterpillars show a 

 certain power of adaptation in repairing injuries to their 

 cocoons, and the methods used by different individuals are 

 not necessarily the same. Thus, according to Kirby and 

 Spence, Bonnet 



. . . . " having opened several cocoons of a moth (Noctua 

 verbasci)) which are composed of a mixture of grains of earth and 

 silk, just after being finished, the larvae did not repair the injury 

 in the same manner. Some employed both earth and silk ; others 

 contented themselves with spinning a silken veil before the 

 opening." 3 



Mr. Romanes also quotes an instructive observation of 

 Reaumur on the larva of the Tinea moth, which eats out 

 the parenchyma of the elm leaf, preserving the outer mem- 

 brane as a coat, and being careful not to separate them at 

 the outer edge where they unite. This edge becomes one 

 of the seams of its coat. The other seam the larva makes 

 for itself. " Reaumur cut off the edge of a newly-finished 

 coat, so as to expose the body of the larva at that point." 



1 Romanes, p. 235. 



2 Brehm, Thieleben, Vol. X. pp. 127, 128. 



3 Quoted by Romanes, p. 236. 4 Ib. p. 237. 



