CHAP. XXII. 1 USEFUL INSECTS. 205 



Chapter XXI i. 

 USEFUL I X s l . < is 



"The stud} ol entomology is one of (he most fascinating ..I pursuits. It lakes its 

 votaries into the treasure-!- Na ire and explains some of the wonderfal series of 



links which fonii the greal chain ol creation 1 . fore us another world, of 



which we have been hitherto unconscious, and shows us thai the tiniest insect, so 

 small perhaps thai the unaided eye can scarcely see it, has its work to do in the world 

 and does it." j G , , 



UNDER the heading of Useful Insects we may consider the 

 comparatively small number of species which are applied directlj 

 to supply the requirements of man. either as food or drugs, or as 

 ornaments, or on account of the products which they yield. 



Silk is the best-known and most valuable of such products and 

 forms the staple industry of many whole districts in India and other 

 countries, amongst which we may mention especially Japan, China, 

 Italy and France. Most caterpillars, and various other insects, and 

 course spiders, spin silk, and we have already seen that the 

 cocoon-making instinct is widely found amongst insects, the basis 

 ot all such cocoons being silk, but it is only in two families of moths 

 that these coitions are suitable for practical use on account of the 

 gth, qualitj and quantity of silk fibre contained in them. 

 These two families, the Saturniadae (or Attacidae) and Bombycidae, 

 1 on, prise a number of species of wild silk-moths which occur more 

 or less commonly in Indian jungles and which are constantly being 

 exploited unsuccessfully by promoters of wild-cat schemes for their 

 commercial utilisation, but the only three species which are of 

 actual value in Southern India are the Mulberry, Eri and Tasar 

 Silkworms. In all cases it is of course only the cocoon, or silken 

 case spun by the larva for the protection of the insect during its 

 resting pupal stage, that is of anj value. 



The Mulberry Silkworm (Bombyx mori) is only cultivated on any 

 scale in Southern India in Mysore and in the Kollegal taluq of the 

 Coimbatore district, this latter area being geographically, if not 

 politically, part of Mysore. As its name implies, this silkworm is 

 fed on the leaves of mulberry, which is generally grown from cut- 

 tings as a field crop, the bushes being plucked ol leaves and 

 regularly cut back when they grow too high. The caterpillars are 

 reared in open basket-work trays made of split bamboo and when 

 full-fed .ire placed to spin theii cocoons in chandrakhis or split- 

 bamboo frames containing a spiral maze in which the caterpillars 



