308 PYRAUSTA MACH@RALIS, 
heavy attack of the pest on scattered trees. Most, if not all, the 
trees will be entirely leafless and the moths willhave to fly some 
distance, during which flight they will be subject to various 
kinds of predaceous animals and insects, before they will find teak 
foliage on which to oviposit. Observations made in the Nilambur 
Plantations, together with information gained there, have shown 
me that the insect there undoubtedly favours the large pure teak 
areas in contradistinction to the mixed teak forest. The trees in 
both young and old forest appearto be equally exposed to this 
defoliation. On the 26th August! portions of the Edakode 
Plantation at Nilambur, and more especially the young 1894 trees, 
were entirely defoliated by Pyrauséta, the leaves still remaining 
on the trees being completely skeletonized and brown. 
The number of insects present and the number of genera- 
tions gone through appear to depend mainly upon two things— 
1. A sufficiency of food material and its collection 
together in pure blocks. 
2. On adamp humid climate, with wet, cold weather or 
early spring rains. In such a climate the trees will 
have a full crop of leaves on them in May when the 
first generation of larve make their appearance. 
In the drier teak forests, when the trees are leafless 
at this period, the number of generations is restricted, The 
evidence as to the number of severe defoliating attacks in 
one year experienced in any one block of forest is conflicting 
at present, as no real records have ever been kept and 
Hyblza puera, whose attacks have not been up to date distin- 
guished from those of the Pyrausta, appears through much the 
same period, Evidence points, however, to at least two more 
or less clear complete defoliations in the year due to the 
Pyrausta, and this may be extended to three. The periods at 

1 A day or two later in the preceding year (1901) I noticed heavy defo- 
liation of young teak by Pyrausta in patches of forest on either side of the 
G. I. P. railway line while the train was running between Hoshangabad and 
Barkhera. The forest in the distance was completely brown. Mr. Hampson 
has since informed me that by the end of September in that year go per 
cent. of the trees in the Kora Range in the Seoni Division were defoliated 
by this insect, 80 per cent. completely so. 
