12 INSECT TRANSFORMATIONS. 



air by this same mist*." *' The farmer," says 

 Keith, *' supposes these insects are wafted to him 

 oil the east wind, while they are only generated in 

 the extravasated juices as forming a proper nidus for 

 their eggst." A more detailed account, however, 

 is given by the late Dr. Mason Good, and as he 

 speaks in part from personal observation, and was 

 not only one of the most learned men of his time, 

 but an excellent general naturalist, his testimony 

 merits every attention • — 



" That the atmosphere," says Dr. Good, " is 

 freighted with myriads of insect eggs that elude our 

 senses, and that such eggs, when they meet with a 

 proper bed, are hatched in a few hours into a perfect 

 form, is clear to any one who has attended to the 

 rapid and wonderful effects of what, in common lan- 

 guage, is called a blight upon plantations and gar- 

 dens. I have seen, as probably many who read this 

 work have also, a hop-ground completely overrun 

 and desolated by the aphis hmmili, or hop green- 

 louse, within twelve hours after a honey-dew (which 

 is a peculiar haze or mist loaded with poisonous 

 miasm) has slowly swept through the plantation, 

 and stimulated the leaves of the hop to the morbid 

 secretion of a saccharine and viscid juice, which, 

 while it destroys the young shoots by exhaustion, 

 renders them a favourite resort tor this insect, and a 

 cherishing nidus for myriads of little dots that are its 

 eggs. The latter are hatched within eight-and-forty 

 hours afier their deposit, and succeeded by hosts of 

 other eggs of the same kind; or, if the blight take 

 place in an early part of the autumn, by hosts of the 

 young insects produced viviparously ; tor, in ditferent 

 seasons of the year, the aphis breeds both ways. 

 Now it is highly probable that there are minute 



* Loudon's Ma jr. of Nat. Hist. i. 180. 

 + Keith's Physiological Botany, ji. 486. 



