Vol. wi No. 5.] The Sexes in HELOPELTIS THEIVORA, 179 
8. 
1. That the males are always present in much smaller num- 
bers than the females 
2. That the more adverse the conditions, the less is usually 
the predominance of females. This is indicated very clearly in 
‘the Behalli results for July, August, September and October in 
the three several years, when the attack was at its height. 
1903. 1904, 1905. 
Number} Males | Number ar Number Males 
of of 
14 of “lo of ° 
insects. Females. insects, |Females.| insects. |Females, 
Jaly ae | 20,446 14:2 12,491 38°6 6,343 52°0 
August . 19,503 10°6 13,685 319 6,089 63°4 
September .. | 18,742] 119 | 11,895 | 34°90 9,360 | 49:2 
October --.| 13,668 10°6 15,393 540 8,328 40°1 
In the first year the efforts at keeping the insects in check on 
these plots were hardly successful ; pes second they were more 
Pp. 
so; while in the third the insects were never able to get out of 
and. The same story = told by the pease given for the second 
place of observation ( tti). 
n explanation of the fact of the sudden drop in the number 
of insects in January or February in each year, it should be noted 
that it is at this season pruning is carried out, and this results in 
the removal and destruction of many ilies of eggs from the 
lants. Hence the drop in numbers is not entirely a seasonal 
variation, 
