MANKIND AND THE INSECT 333 



East ; but the cocoons of several large Saturniid moths 

 have also been utilised in recent years. Three centuries 

 ago, honey was the only sweetening agent in common 

 use. To-day, its place is taken by cane- and beet-sugars. 

 Nevertheless, the incomparable virtues of honey are well 

 known, and its annual consumption in all civilised countries 

 is still very considerable. Pure beeswax is also less in 

 demand than heretofore, chiefly because many of the 

 uses to which it was once put are now served by wax 

 obtained from various plants and minerals. At the 

 present day, the largest demand is for the manufacture of 

 candles employed in religious ceremonial. But beeswax 

 retains its ductility and tenacity under greater ranges 

 of temperature than any of its competitors in commerce, 

 and thus, for certain purposes, it remains indispensable. 



Strangely enough, the family of the scale insects 

 (Coccidce). which includes very many devastating pests, 

 also comprises a number of species which secrete sub- 

 stances valuable to mankind. The "manna," endowed 

 by the wandering Israelites with a miraculous origin, 

 was almost certainly a kind of honey-dew produced by 

 Gossypcwia mannifera, a coccid found on tamarisks in 

 the Mediterranean region. The substance is still used 

 as food by the Arabs, who call it "man." The white 

 wax of China is secreted by Ericerus pe-la — a scale 

 insect found upon the Chinese ash tree. It was formerly 

 greatly prized, but is now falling into disuse owing to the 

 introduction of kerosene. In India, a similar wax is 

 secreted by a scale insect known as Ceroplastes ceriferus, 

 while the wax produced by several other species of this 

 genus has been utilised by mankind. The Mexican 

 coccid Llaveia axinus yields a fatty substance from which 

 a peculiar acid (axinic acid) is derived. This is used 

 as a varnish, which dries and hardens on exposure to 



