•I. IX.] THE COCHINEAL-INSECT. 169 



figures of the female cochineal-insect, magnified, 

 will ffive a good idea of this genus generally. 



Their tnmk is so brittle that they cannot be moved 

 Irom their place without breaking it; an accident 

 which would prove fatal to them : the consequence 

 is, that during the whole term of their life they re- 

 main fixed to the spot where they first settled, and 

 to the vegetable nipple which feeds them. When 

 the females have attained the age of puberty, the 

 males are supplied with wings, and enabled to quit 

 the plant on which they were hatched. The females 

 remain stationary, and hatch their young on the 

 spot ; but the latter would soon become so numerous 

 as to be at a loss for space to feed on, while they 

 are so delicate, that it would be impossible for them 

 to pass from one plant to another, if nature did not 

 provide for them admirable means of emigration: at 

 the period of their birth a multitude of spiders fasten 

 their nets to the leaves of the nopal ; and it is along 

 these slender threads, which answer the purposes of 

 a bridge, that the brood of the cochineal-insect emi- 

 grates to a neighbouring tree in quest of food. 



The gall-nuts used in making ink are produced by 

 an insect which punctures the leaves of a species of 

 oak very common in Asia Minor, where they are 

 ';ollected in considerable quantities by the poorer in- 

 habitants: from the different ports' of the Levant 

 they are exported to various parts of the world 

 Tlie galls held in the greatest estimation are those 



