264 



ANIMAL PARASITES AND MESSMATES. 



originally from Mexico, lives on the cactus nopal as a 

 true parasite, and furnishes a precious colouring 

 matter, carmine. This insect has been introduced into 



I 



Fig. 81.— Cochineal insect, female. 



the Antilles, Spain, the Canary Isles, Algeria, and 

 Java. 



Lake is produced by a species of the same genus, 

 originally a native of India {Coccus lacca). 



Aphides (Fig. 82) feed on the sap of plants ; they 



multiply rapidly without the male insect. Eose-trees, 



and more especially their buds, are attacked by a species 



of a green colour, of which we give a representation 



(Fig. 83). ^ 



An aphis, the Phylloxera vastatrix, has, a short time 



since, invaded the vineyards, and small as it is, it is 



dreaded as a plague which scatters ruin in its path. 



According to recent observations this insect has a 



double series of generations which precede each other : 



the mother type and the tubercular type. But this 



polymorphism seems to be more apparent than real, 



