Indian Forest Records. 
6 
[Vol. VIII 
(4) Prevalence of natural enemies of the insect or the host-plant; 
including various predators and parasitic animals, 
human thieves, and fungal or bacterial diseases. 
Unfortunately, very little is accurately known about any one of 
these four points. With regard to (1) and (2) our ignorance at pre¬ 
sent is practically complete. We do not know what substances in the 
plant the lac insect really feeds on, or what condition of the plant 
favours the production of these substances ; nor have we any clear 
ideas as to the characteristics of different varieties of the lac insect 
and their relative efficiency as lac-producers. It is known that lac 
itself, including the lac-wax and dye that are also produced, is a 
complex substance made up of at least half a dozen different com¬ 
pounds ; but of the physiological processes whereby it is made and 
secreted by the insect we are entirely ignorant. 
As to point number three (weather and climate) we know that 
strong and dusty winds, frost, hail and heavy rain are all likely to 
cause serious loss at the critical periods of larval and male emergence ; 
but as regards what may be called climatic distribution we have no 
definite or precise knowledge. That is to say, given an acquaintance 
with the meteorological data relating to the temperature, rainfall, and 
humidity of any particular place, we cannot say definitely whether 
that place is climatically suited to the lac insect or not. 
With few exceptions, insects are affected by climate far more 
than we are, and are unable to live a healthy life, or even live at all, 
outside their own particular limits of temperature and humidity. 
These limits thus decide the climatic suitability, or otherwise, of any 
geographical area for the cultivation of any given kind of insect; 
and in a case like that of the lac insect, where extension of cultivation 
is desirable, waste of money or energy may be avoided if the limits, 
and the optimum conditions which lie somewhere between them, are 
definitely ascertained. 
All that we know at present is that areas where lac is at present 
most abundantly grown, namely, Chota Nagpur, Orissa, and the east 
of the Central Provinces, are generally over 1,000 feet above sea-level 
and enjoy a fairly temperate climate. The annual rainfall is from 
50 to 60 inches, and occasional showers are secured during the 
winter and summer months, outside the regular rainy season. The 
general humidity is low. Frost, although fairly common in parts 
M 
