5 
Part I.] Beeson : Life-History of Diapus furtivus, Sampson. 
to remark here on its connection with insect pests. The diseased or 
dying state of the roots produces the condition of unhealthiness in the 
tree, which is essential for successful attack by insects. With the greater 
part of its root-system put out of action the tree is unable to offer resist¬ 
ance to a heavy attack by secondary borers and succumbs rapidly. 
The chief point established by the investigations recorded above 
indicates that Diapus furtivus is not primarily responsible for the dying- 
off of Sal in Bengal, as was supposed at the commencement of opera¬ 
tions, but that it is a member of a group of borers which attack dead 
and dying Sal, and under normal conditions is a secondary pest. Its 
economic status as a secondary pest in Sal forests is referred to on 
page 27. 
Synonymy of the Species. 
Diapus furtivus, Sampson. Fam. Platypodidae. Coleoptera. 
Diapus sp., Stebbing, Forest Bulletin, No. 11, 1907, p. 42 ; Plate 
VI, fig. 10. 
Diapus furtivus, Sampson, $ £ (lege s $ ); Ann. Mag. Nat. Hist., 
Ser. 8, XII, 1913, pp. 450—451. 
Diapus mirus, Sampson, (lege $ ), loc cit., p. 452. 
Diapus furtivus , Stebbing, Indian Forest Insects, 1914, pp. 630— 
632, fig. 398 (lege ). 
Diapus mirus, Stebbing, loc cit., p. 633, fig. 399 (lege d). 
Diapus furtivus, Beeson, Indian Forester, XLI, 1915, pp. 298— 
299. 
Diapus furtivus, Beeson, Indian Forester, XLII, 1916, pp. 222— 
224, Plate 16. 
Diapus furtivus, Gra/vely, Records of the Indian Museum, XI, vi, 
1915, p. 504. 
Distribution. 
The species appears to be distributed uniformly through the Sal 
forests of the Sub-Himalayan tract and of Central India, though more 
information is available as to its prevalence in the former region. 
Specimens in the Dehra Dun collection originated from the following 
forest divisions :— 
Assam. —Garo Hills, Goalpara. 
Bengal. —Jalpaiguri, Buxa, Tista, Darjeeling. 
United Provinces. —Lansdowne, Gonda, Kheri, Ramnagar, Siwalik. 
Central Provinces. —Mandla. 
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