30 BULLETIN 746, U. S. DEPARTMENT OF AGRICULTURE. 
tality among those which escape and hibernate, it is evident that 
comparatively few emerge in the spring. Yet there is always a 
heavy infestation by fall. The rapidity of reproduction during the 
warm months is the only factor which can account for this high 
infestation. 
The record of oviposition for 56 moths at various times during 
the season of activity shows that each female moth deposits on an 
average 210 eggs. The sexes are produced in equal proportions. 
Allowing 200 eggs for each female and four generations a year as a 
conservative estimate, it is found that each pair surviving the winter 
is capable of producing the following numbers : 
Generation. Borers. 
First 200 
Second 20, 000 
Third 2, 000, 000 
Fourth 200, 000, 000 
Total 202,020,200 
Of course this maximum number will never be produced, because 
of the numerous checks which control the insect, but something of 
its enormity may be realized by considering that if the offspring 
of one female were confined to 1 acre there would be over 10,000 
borers per stalk of cane, about 20,000 stalks being the average per 
acre. Under average conditions about 50 per cent of the stalks are 
infested and about 25 to 30 per cent of the infested stalks contain 
borers when cut for the mill, giving from 2,500 to 3,000 borers per 
acre. Considering the possibilities, it is only surprising that the 
infestation is not much higher. 
PROGRESS OP INFESTATION. 
The moth borer is late in developing in the spring. The first 
" dead heart " at New Orleans is usually found about the 1st of May, 
which indicates that moths have emerged from hibernation several 
weeks previously. Not much injury can be found through the sum- 
mer, but the numbers of borers gradually increase. When the corn- 
stalks become dry in July and August the emerging moths un- 
doubtedly migrate to sugar-cane fields in large numbers. The 
infestation increases rapidly from about this time until the cane is 
cut for grinding. 
STATUS EXAMINATIONS. 
Field examinations to determine the annual status of the moth 
borer and other sugar-cane insects have received considerable atten- 
tion from the writers. The best and practically the only time to 
determine borer injury to sugar cane is during the grinding season 
