40 
INTRODUCTION. 
assist in keeping the earth sweet and wholesome, and in rapidly restoring 
to the soil available food ; with the bacteria, the fungi and similar organ¬ 
isms, they play a great part in the constant cycle of matter through the 
soil to some form of life and back to the soil again. In these ways insects 
assist agriculture directly. Another great function they exercise is in 
pollination ; a large proportion of plants are dependent upon insects 
for their fertilisation and we largely owe the beauty of many flower forms 
of the plant world to the need the plant has of attracting the insect and of 
inducing it to carry the pollen. The significance of insects in this respect 
requires no proof ; one can observe it both in the plants themselves and 
in their numerous insect visitors. 
Indirectly insects are also a benefit as they check themselves and also 
help to keep down the undue prominence of weeds and particular forms 
of plant life. It is perhaps a paradox to ascribe as a virtue to insects 
the fact that they check themselves, because, if they did not exist, no 
check would be needed ; still it is a sober fact that parasitic insects are 
an important part of the insect world, and if they were absent for a few 
weeks, India would starve. Finally, there are the useful insects. These 
are connected with :—(a) silk, (b) lac, ( c ) wax, ( d) dyes, (e) medicine, 
(/) food for man, ( g ) food for domestic animals, ( h ) ornament. 
Those that yield silk are perhaps pre-eminent at present since im 
portant industries are dependent upon the silk excreted by the pupating 
caterpillar of one of four moths. The value of the exported silk in 
1906-7 was 204 lakhs, but much more was produced and used in the 
country itself. 
Lac is a large industry, one of the big staples of India, and, since its 
use is yearly growing and the source of supply is limited, it is an industry 
that brings increasing wealth to this country. The export in 1904-5 
was valued at Us. 3,47,00,000 and, besides that, a large amount was used 
in India. 
Wax is still an article of export, fetching a high price and we may 
see established in the future a large industry in the domesticated bee, 
for the production of both wax and honey. The yearly export for the 
last twenty years has fluctuated between 3,000 cwt. and 7,000 cwt. ; 
the value being between 2|- and 7 lakhs. 
The importance of insects as dye producers is gone. Even lac is of 
no value except on a small scale. Medicine is still dependent upon insects 
