10 
Indian Forest Records. 
[Voi,. VIII 
the winter brood on Kusum emerges during December-January, and 
on other trees during late October-December. There are, however, 
considerable local variations in these periods, some particulars of 
which have been recorded t by Imms and Chatterjee. It is of great 
importance that the swarming periods should be carefully determined 
for each lac-growing area and for each important “ host ’’-tree. Imms 
and Chatterjee quote an exceptional case in which, in 1913, samples 
of stick-lac from the Kheri forest swarmed on February 22nd. A 
parallel instance was observed by Lindsay, when stick-lac that had 
been kept for some time in bags in the Rang Lai factory at Ranchi 
swarmed on exposure to the light. Observation in the laboratory 
indicates that at certain stages the swarming larvae are “ positively 
heliotropic ”; in other words, they go towards the light, e.g> of a 
sunny morning, and it may thus be possible to delay the swarming of 
brood-lac by keeping it in a light-tight receptacle. This might under 
certain circumstances be of considerable practical value in connection 
with the collection, storage, and transport of brood-lac from one 
locality to another. 
Vague statements have appeared to the effect that in Mysore 
and Burma there are lac insects which breed three times in a year 
instead of twice. Whether this is the case or not remains to be 
seen, but it is interesting to note that lac from Shorea Talura in 
Bangalore, which originated from a swarm in the latter part of 
December, swarmed on April 21st in the laboratory at Dehra Dun, 
a remarkably early date. This seems to be the most definite 
evidence as yet available as to the existence or otherwise of this 
tri-voltine breed ; but the possibility of getting three crops instead 
of two is certainly of interest. 
It is from every point of view desirable that a comparative study 
of the different varieties of lac insect from different areas should 
be made in order to arrive at some definite knowledge of their 
hardiness, adaptability to particular host-plants, and lac-producing 
efficiency. The fact that we are still unable to say whether there 
is, or is not, a tri-voltine variety of an insect of such great com¬ 
mercial importance is an indication of the extent to which its 
general study has been neglected. 
There is one particular side of its study—the physiological 
side—which has also been entirely neglected, perhaps on account 
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