28o 



Marvels of Insect Life, 



the leaf, but soon covers it with a most unsightly black deposit like soot, which 

 utterly spoils the appearance of peaches and other glass-grown fruit. 



On the other side of the account, it must be pointed out that scale-Insects 

 produce some substances that are of importance in human industry. There is, 

 for example, the valuable substance known as " lac," which is the basis of French 

 r ^ ' - polish, varnishes, and sealing- 



wax. This lac is excreted by 

 the female of an Indian scale- 

 Insect,^ and forms resinous 

 masses upon the twigs where 

 the Insects feed. The female 

 herself yields the beautiful 

 colour which artists distin- 

 guish as lake. Then there is 

 cochineal, which at one time 

 was one of our important 

 articles of commerce as a 

 dye-stuff, and is still used as 

 a colouring-matter for medi- 

 cines, sweetmeats, and as a 

 cure for \\'hooping-cough. It 

 consists of the bodies of several 

 species of coccus that feed 

 upon the prickly-pear and 

 other cacti. The manna of 

 the ancients is believed to be 

 the secretions of a coccus - 

 that is found on tamarisk in 

 the countries around the 

 Mediterranean, where it is 

 still used as food. Several 

 Indian and Cliinese species 

 produce a beautiful white wax 

 in sufficient quantitv to make 

 it worth while gathering. At 

 least, it was worth while before 

 the production of solid kero- 

 sene for the manufacture of 

 candles restricted the use of 

 real wax for tliis }')urpose. 

 Some of our native species are wax-producers, but not in such quantity as to make 

 them commercially im])ortant. The Chinese and Indian species referred to ^ 

 produce it in the form of long, woolly streamers covering the bodv. Our most 

 conspicuous example of these wax-producers is the felted beech-scale,* which makes 

 old beeches to look as though they had been in a recent snow-shower. The Insects 



1 Tachardia lacca. ^ Gossyparia mannifera. » Ericcrus pda and Ccroplastcs ccrifcia. 



* Cryptococcus lagi. 



Photu by\ [E. Step, F.L.S. 



An Insect Kecklace. 



These necklaces, worn by native ladies in South Africa, are known as being formed 

 of ground pearls. They are really a species of scale-Insect that attacks the roots of 

 certain trees. At a particular stage in their career the females cover themselves 

 with a secretion which hardens intoa horny shell, varying in hue from clear yellow 

 to brown. In these closed cells the Insects are believed to remain often for years 

 before completing their development. 



