20 
Indian Forest Records . 
[Vol. VI 
met with mainly in the pupal stage. On the 20th, the beetle was taken 
abundantly on the wing round a recently dead tree (S. T. 16), the leaves 
of which had not yet fallen. The tree was badly attacked by Hoplo- 
cerambyx spinicornis, while earlier flights of Diapus furtivus had recently 
established in the upper part of the bole. On the other hand, in two 
dead trees (S. T. 17 and 18), examined in the same locality on the same 
date, the development of the borer was represented mainly by late larval 
and pupal stages. 
At the end of the month, 25th-29th, swarms of Diapus furtivus 
were frequently met with. Logs freshly attacked by the borer were 
collected on 16th December and sent for breeding experiments to Dehra 
Dun. The emergence records (R. R. D. 76) show a fairly steady 
appearance of Diapus furtivus from the 10th of February to the 6th of 
March, i.e ., through a period of from 8 to 12 weeks after collection. 
As it is very probable that eggs were laid about a fortnight before, and 
after the 16th December the emergence dates agree with the assump¬ 
tion that the life-cycle occupies about 10 weeks. The Divisional Forest 
Officer, Darjeeling Division, Bengal, in December 1915 sent a Sal log 
from a tree felled on the 25th November 1915 in Tista-Takdah Range 
(R. R. D. 67). This was examined at Dehra Dun on the 28th Decem¬ 
ber and early work of Diapus furtivus observed. The beetles had paired 
and commenced excavation in the sap-wood but no eggs had been 
laid. 
In January 1915, the writer toured in Buxa Division, Bengal, and 
obtained the following field records :—On the 11th, in a tree which had 
died several months before (S. T. 55A), traces of completely matured 
broods of Diapus furtivus were recognized. All beetles had swarmed 
with the exception of a few stragglers. On the 15th, in a recently dead 
tree, which still retained the shrivelled leaves (S. T. 67), early work 
of Diapus furtivus with eggs and newly hatched larvae was found. A 
few days later, in another tree (S. T. 61), dead some months before, 
the late pupal stages of the borer marked the general stage of develop¬ 
ment. During this period swarming beetles were occasionally taken 
on the wing. 
A similar development to this in Assam is indicated by the results 
obtained from the insectary records of specimens collected by Forest 
Ranger D. C. Ghosh in Guma Range, Goalpara Division, Assam. A 
tree attacked by Hoplocerambyx and shot-hole borers was felled in 
September 1915, and logs cut and despatched to Dehra Dun on 1st 
December 1915 (R. R. D. 61). The emergence of Diapus furtivus 
is given in the table below. 
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