HOMOPTERA. 



171 



wonder how any of them escaj^e from such hosts of hungry 

 and relentless foes. 



Let us not imagine, however, that these insects have 

 been created in such numbers merely for the purjDose of 

 destroying vegetation, and of affording food to voracious 

 persecutors. Man, as we shall soon perceive, has by no 

 means been forgotten in their distribution. 



The Coccidae, so called from the valuable Grecian dye, 

 KOKi^og, more than counterbalance, by the richness of 

 their productions, all the devastation caused by the 

 Aphides we have been describing, and various Eiu'opean 

 and Asiatic species are soui-ces of considerable wealth 

 to the countries where they are found ; but the discovery 

 of 



The Cochineal Insect (Coccus Cacti), which Hves in immense num- 

 bers on the Cactus Cochinelifer, from tlie brilliancy of the colour it 

 affords (cochineal), has thrown the dyes derived from other species 

 into the shade, and has proved one of the most productive sources 

 of wealth to the countries where it is cultivated. Another impor- 

 tant species, tlie Coccus lacca, furnishes the valuable Indian product 

 called lac, an article of so much importance in the manufacture of 

 varnishes, sealin2:-wax, &c. Another species of Coccus is found 

 upon the Tamarix mannifera, a large tree which grows in Syria. 

 The female insects, puncturing the young shoots, cause them to 

 discharge a vast quantity of a peculiar secretion (manna), which 

 quickly hardens, and drops from the tree, where it is collected by the 

 natives. Other sijecies produce in abundance a substance almost 



Upper surface. Under surface. 



Fig. 131. -cochineal insect. (Magnified.) 



identical with wax. The Chinese collect it at the approach of 

 autumn, by scraping the boughs on which it is found. It is then 

 melted and strained into cold water, when it hardens, and is made 

 into cakes exactly resembling white wax, and is used for similar 

 purposes. Various otlier important results of their industry might 



I 2 



