Part I.] Beeson : Life-History of Diapus furtivus, Sampson. 17 
SEASONAL HISTORY.* 
Seasonal History in Bengal and Assam* 
In August 1914 logs of Sal attacked by Diapus furtivus were collected 
in Buxa Division, Eastern Bengal, by Deputy Banger B. K. Kashta, 
and Sent to Debra Dun. The emergende records of two logs A and B 
are given below in Table II. 
The tree (S. T. 56), from which the specimens were taken, stood in 
Compartment 18, Rajabhatkhawa Block, Buxa Range, Buxa Division, 
in an area of considerable mortality among the older trees. In January 
1915, the writer visited the area personally and ascertained that all the 
trees had been attacked by the Sal root-fungus, and that their deaths 
were to be attributed primarily to that cause. The tree (S. T. 56) 
was noticed by the Banger to be newly dead on 18th August 1914, and 
on examination early stage work of Hoplocerambyx spinicornis, and 
Diapus furtivus was found. Beetles of the latter species were collected 
on the bark and boring into the sap-wood. The tree was felled on the 
29th August and a log about lS^ long, Log. A. (R. B. D. 62) was sent 
to Dehra Dun for breeding experiments. Beetles and eggs of Diapus 
furtivus and of Sphaerotrypes siwalikensis were collected at the same 
time. 
On the 27th September 1914 the Banger, at my request, sent a second 
log from the same tree. The emergence records from this log, B, 
(B. B. D. 65) are given in the Table below. 
* The terminology of “ seasonal, and life-history,” “ brood,” “ generation, ” etc., 
used in this bulletin is that proposed by Hopkins (1909, pp. 38—41) in his monograph 
on the genus Dendroctonus. 
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