Insects. 2239 



the condition of infancy to age, has separate duties to perform in every stage :— joys 

 that are congenial to each period, and separate dangers to escape. The proportions 

 of these may differ ; for man varies from other animals, in passing through a longer 

 state of pupilage; and there is also assigned to him the period of old age, which is a 

 valuable condition in the system of human life, but which wild animals would find a 

 state of unmixed suffering. But, setting aside these exceptions, his animal life does 

 not differ more from that of other creatures than theirs from each other. So different 

 are the ideas, wishes, and modes of action, of one stage of existence from that of ano- 

 ther, that if consciousness could be withdrawn but for an instant, the comparison 

 would scarcely leave him to suppose himself to be the same person. It is one of the 

 analogies in Nature to which we have referred. The changes which thus pass over 

 man and many other creatures in the ordinary mutations of their lives, and which are 

 comprised in the successive development of organs, with their subsequent inactivity 

 and decay, are in others, of a lower rank, brought about by a process almost resem- 

 bling a new creation $ and which condition, because it appears more perfect, and 

 sometimes lasts for an exceedingly short portion of time, has caused it to be said that 

 their lives are reduced to the very shortest span. Such is the case with the Epheme- 

 ra fly ; and, as many insects enjoy a sportive existence for many weeks or months in 

 the summer, pity has been expressed for the frail condition of a creature which in a 

 very few hours must die either from exhaustion or old age. But it should be remem- 

 bered that a much longer period of its life has been passed in a state which, to the 

 creature, was not less a condition of enjoyment ; and that the short-lived winged con- 

 dition is assumed only for a brief space in order to accomplish a specific object not 

 otherwise within its powers. The suddenness with which the change is begun and 

 ended, and not the greatness of the mutation, is the chief subject of our surprise and 

 admiration. 



The insect genus Aphis includes many species, but they resemble each other in 

 their most curious particulars. The Aphis is a little obscure fly which would escape 

 attention if it did not sometimes appear in enormous numbers, and show itself capa- 

 ble of inflicting injury on some valuable vegetables, by piercing the skin and sucking 

 the sap. Curiosity could scarcely fail to be excited by the manner of their appear- 

 ance; for they are commonly found suddenly congregated in situations to which they 

 could not have ascended from the ground ; and it is difficult to imagine how they 

 could have arrived through the air, for few, perhaps none that are visible, are furnished 

 with wings. Their habits are inert, and they are as incapable, as they are indisposed, 

 to wander from their situation. 



The researches which explained the mystery of the first appearance of this insect 

 developed a series of circumstances still more unaccountable. It was found that, un- 

 like the Ephemera, which assumes its winged condition for the purpose of depositing 

 its eggs, for in this state only is it capable of continuing its race, the Aphis multiplies 

 its kind only in the wingless or penultimate state ; the young ones being produced 

 alive, in a form that differs from the parent only in size. But while through the 

 summer all the parents, for nine successive generations, are fertile females, yet when 

 winter is near the final brood is constituted of both sexes, and eggs are deposited, 

 which endure the cold, and, in spring, produce the broods that again pass through this 

 remarkable process. 



There are insects which deposit eggs when in the condition of larvae or maggots, 

 which is a degree considerably short of the full development of their perfect typo, and 



