Part I] Lindsay and Harlow : Lac and Shellac nj 
in different areas from the attacks of parasites. Correlation of 
parasite abundance with climatic or any other conditions. 
3. Determining whether or not the various parasites have “ alter¬ 
native hosts ” other than the lac insect. Dr. Imms’ scheme is as 
follows : that an isolated area should be planted with lac, only one 
crop (Katki) being taken in the year ; brood-lac for inoculation would 
be brought in each year for say three years from some locality 
relatively free of parasites. The amount of parasitic attack would be 
carefully watched; if it remains slight throughout, the lac insect is 
probably the only host of the parasites concerned ; if it increases, 
the lac is probably being infected by parasites reared on other hosts 
in the neighbourhood. 
4. If alternative hosts are present, the possibility of destroying 
the parasites through destruction of the alternative host at certain 
seasons. 
5. Period of late emergence of parasites and utility of measures 
such as fumigation. 
6. Determination of the relative severity of parasitic attack on 
lac of different varieties or from different food-plants. 
7. Determination of the means whereby the parasites discover 
the lac insect at the particular stage in its career when they are 
accustomed to infect it. If by the smell of the lac, can the 
odoriferous substance be isolated and used as bait to destroy them ? 
Are repellent sprays practicable ? 
8. The discovery of l( hyper-parasites ” and other enemies of 
the parasites ; the possibility of using them as means of defence. 
9. Using all facts obtained to help in devising methods of 
evading, repelling, trapping, disabling, or destroying parasites. 
C— Work on the Lac Insect. 
(a) Entomological . 
1. Study of the external structure of insects from different 
localities and food-plants, to ascertain the existence or otherwise of 
definite morphological species or varieties. 
2. Study of the life-history of the insect, with special reference 
to the period of emergence in different localities, and the influence 
thereon of temperature, humidity, altitude, and foo‘d-plant. 
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