35 
of the weather. It is almost certain that these minute "insects are not 
active during rainy Aveather, as they could scarcely live under such 
conditions. It is further probable that the}^ are actually destroyed in 
large numbers b}^ the rain, despite their efforts to secure safe retreat. 
As opposed to the favorable influence of rain}^ weather on the boll- 
worm b}^ interference with the work of its natural checks must be 
mentioned the considerable destruction of eggs under the same condi- 
tions which are favorable to its increase in other stages. A heavy rain 
has the effect of washing from the plants to which they are attached 
man}^ of the eggs, the great majority of which are destroyed by the 
combined mechanical effects of the rain and particles of soil. Fre- 
quent observations before and immediately after heavy rains leave no 
doubt that many eggs are thus destroyed. 
The foregoing remarks have been confined to an explanation of 
some of the factors involved in the greater destructiveness of boll- 
worms to cotton following rain}^ weather in late July and in August. 
The month of August, including during some seasons the last week or 
ten days of July, marks the period of danger from bollworms. The 
tendency on the part of the planters has been therefore to limit the 
influence of weather conditions to about this period. The insect, how- 
ever, is subject to these same conditions in its several generations 
from early in the spring until late in the fall, and during the winter 
the pupae in the ground are probably much influenced by climatic con- 
ditions. The possibilit}^ of severe injury to cotton in July and August 
therefore depends also on how they have been able to maintain their 
numbers during the balance of the year. Owing to their rate of mul- 
tiplying in geometrical progression, the destruction of a pupa during 
the winter, or of a larva in young field corn in the spring, would 
diminish the possible number of bollworms ready to attack cotton in 
August by many thousands. Their abundance or scarcity on cotton 
is therefore seen to depend on other conditions than those existing 
during the immediate period of injury. 
INJURY TO COTTON FROM OTHER CAUSES THAN THE BOLLWORM. 
The known capabilities of the boll worm to injure cotton has led to 
its being charged with practically all forms of injury affecting the 
squares and bolls, aside from that done by the boll weevil, and the 
seriousness of its ravages has thus often been greatly exaggerated, 
especially by those not accustomed to examine closely into matters of 
this kind. As is shown on a later jmge, there are a few insects affect- 
ing both corn and cotton which might, from the character of their 
work, be mistaken for bollworms. These are, however, relatively 
unimportant in the extent of damage. Certain hemipterous insects, as 
Calcoris rapidus Say, HornalocUsca trtquetra Fah., and Largus cinctus 
