THE SEXUAL INSTINCT. 513 



African migratory locust is specifically different from the European 

 one. Whether the migrations of the Libellulee have the same object 

 cannot be ascertained with certainty, but it is improbable, as they are 

 carnivorous. 



NINTH CHAPTER. 



OF THE CONSERVATION OF THE SPECIES. 



THE SEXUAL INSTINCT. 



291. 



THE impulses which nature has implanted for the conservation of 

 the species are more evident than those for the preservation of the 

 individual. We have before hinted that all the several conditions of 

 insect life appear to have for their chief object the conservation of the spe- 

 cies, and we have also ascertained that the life of the individual termi- 

 nates with its sexual activity, it having thereby fulfilled the object nature 

 contemplated through its means, and it may then quit the stage. If 

 now, therefore, we collectively comprise together the several phenomena 

 which refer to the sexual functions, we shall find them to consist of 

 two chief divisions, under which the various functions may be classed. 

 These are, the impulse which brings the sexes together, the copulative 

 impulse, and that which urges the impregnated female to take such 

 care of her eggs and young that they may thrive under favourable cir- 

 cumstances, an impulse which admits of comparison with the maternal 

 love of the human race, and which in insects also exhibits itself in the 

 anxiety of the parent for her progeny. 



I. COPULATIVE IMPULSE. 

 292. 



This impulse presents itself in insects so soon as they have attained 

 their perfect state, and it henceforward predominates throughout the life 

 of the individual. The duration of the lives of insects depends upon 

 their copulation, for the majority die speedily after its accomplishment, 

 and only those which have been prevented from the act can survive 



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