50 PARASITES OF THE COTTON BOLL WEEVIL. 
V. CONCLUSIONS AND PROSPECTS. 
In conclusion the writer would say that there are a number of very 
important points obtained which indicate a possible natural control 
of the boll weevil. The actual combinations of conditions which 
bring about the instances of high parasitism can not be understood. 
It is very evident that the elements in the combination are relative 
moisture and light, plant response to. weevil injury, abundance of 
other species of weevils in the immediate vicinity, and, finally, the 
ability for rapid adjustment to new host relations possessed by the 
local parasites. 
Very high parasitism has been found, and it may therefore be 
expected again, perhaps locally,. perhaps regionally. It may not 
necessarily be expected two years in succession at the same place, 
for a change in cultivation, an eradication of certain surrounding 
plants, or various other conditions might destroy the advantages pre- 
viously gained. On the other hand, these same agencies in another 
locality might attain the opposite result. 
Release of parasites in the open field on a small scale has been 
found to increase the rate of parasitization. This will be tried on a 
more extensive and better planned outline another year. 
‘The abundance of hosts which have parasites in common with the 
weevil and the fact that parasitization takes place in the first genera- 
tion give promise that the weevil’s advance may be constantly dis- 
puted by the parasites. 
