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 



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, 



