XXI 



occurs for Instance in Java in those of Adolias Adonia Cram. ; besides, the 

 same fact has already been observed elsewhere respecting other butterfly-species. 

 The said larva feeds on the leaf of a Loranthus species growing parasitically 

 on trees; the thick, pulpous stem of that leaf very easily breaks off from the 

 branch on which it grows, in which case, of course, the leaf falls on the ground. 

 Against such a leaf the larva attaches itself, so that, during the chrysalis 

 state, it is much exposed to the danger of the leaf being accidentally torn from 

 the branch and falling to the ground, which in most cases will cause the death 

 of the pupa. But it knows how to avert this danger ; as soon as the leaf has 

 been chosen to which it is going to fasten itself with a button of silk in order 

 to pupate there afterward, it first of all fastens the stem of the leaf by means 

 of some threads of silk strongly to the branch, so that if, during its pupal stage, the 

 leaf should by any unexpected accident break of from the branch, it must 

 yet remain fastened by the threads of silk, whence the fall of the leaf will cause 

 no danger to the pupa. The larva, then, knows how to take well planned 

 measures against a future danger which may, but need not necessarily, come 

 to pass. Once I saw such a larva fasten to its own leaf, with a few threads of 

 silk, on two sides, another leaf that had accidentally grown before the leaf it 

 had selected for Itself, so that fastened In such a manner it must always remain 

 before It, so that the pupa, when it afterwards became attached to the leaf, 

 would be hidden from sight, from approaching birds, squirrels and other animals 

 that prey upon pupae. 



Measures against future danger of which the larva must know the nature 

 as well as the possibility. The existence of the here mentioned pupae-enemies, 

 the peculiar fragility of the stem of the LoRANXHUs-leaf, the coming of its 

 own helpless pupal stage when attached to the leaf, must therefore be known 

 to It. It is, in fact, nothing wonderful that larvae possess the intellectual power 

 to take such measures. That many insects have a strong intellectual development 

 Is well known. With the ants this Is the case In a very high degree, but also 

 In other classes of animals we find remarkable instances of it. As for the 

 Lepidoptera, many manifestations of the psychical nature have been made 

 known of these Insects too. Such facts as the love of cleanliness spoken of above ; 

 sometimes, as for instance the removing of the cast larva-skin from the cocoon 

 by the larvae of Chionaema Javanica Butl. and C. Bianca Hamps. — described 

 by me in the XLVII"" volume of the Tydschrift voor Entomologle — performed 

 with evident reflexion, are undeniable manifestations of such a psychical nature. 

 These manifestations appear more particularly In the larvae when they are In 

 those critical periods of their life that are connected with the process of 

 pupating. Here belongs the case which gave rise to this discussion ; even the 



