552 INSECTA. 



the highly-developed perceptive powers of the .sense organs. The 

 animal enters the world with instinct, but, in order to perform acts 

 depending on memory and judgment, it must first acquire the 

 necessary psychical conditions by sense perceptions and experience 

 (bees). In the inherited organisation are latent all those capabilities 

 which have been acquired in the gradual processes of phylogenetic 

 modifications and at the expense of psychical forces, and have, at 

 last, as the result of frequent use, become automatic and a 

 pure mechanical property of the organism. 



The instinctive and psychical manifestations tend directly to the 

 preservation of the individual by providing ways and means for the 

 acquisition of food and for protection, but there is a special instinct 

 tending to the preservation of the species and the care of the young. 

 The most simple example of the latter is to be found in the judicious 

 deposition of the eggs in protected localities, and on plants suitable 

 for the nourishment of the just-hatched animal. The actions of the 

 mother become more complicated in those cases in which the larva 

 develop in specially prepared places, and have, as soon as hatched, to 

 meet with the requisite amount of suitable nutritive material (Sphex 

 sabulosa). But most wonderful are the instincts of some of the 

 Orthoptera and Hymenoptera, which concern themselves about the 

 fate of their young after they are hatched and carry nourishment to 

 them during their growth. In such cases a great number of indivi- 

 duals become associated together for the common welfare in the 

 so-called animal communities, in which there is a marked division 'of 

 labour among the different members; males, females and sexually 

 aborted forms or neuters (termites, ants, wasps, bees). 



Some insects are capable of producing sounds,* which we must 

 in part regard as the expression of an internal disposition. We 

 cannot, however, thus regard the buzzing sounds produced during 

 flight by Hymenoptera and Diptera (vibration of wings and of the 

 foliaceous appendages within the tracheae), or the sounds like those 

 of a rattle which are produced in numerous beetles by the friction of 

 certain body segments against one another (pronotnm and mesonotum 

 of the Lamellicornia) or with i,ho inner sides of the wing-covers, 

 although it is possible that such sounds are of some use for defence 

 against hostile attacks. Peculiar vocal organs, which produce sounds 

 for the purpose of attracting the females, are found in the male 

 Cicada on the abdomen, and in the males of the Gryllidw and 



* H. Lanclois, " Die Ton-unrl Stimmapparate cler Insecten." Leipzig, 1867. 



