SEASONAL. STUDIES OF INSECT CONTROL. 



15 



hangs by a few threads and dries on the plant. (PI. I, fig. 2 ; fig. 3, 6.) 

 To these squares and bolls which thus hang, we have applied the 

 terms "hanging squares" and "hanging bolls." 



Tables II and III, which are arranged to show the monthly per- 

 centages of control by parasites, by predators, and by all insects, 

 illustrate the differences in the control of the weevil in the four 

 principal classes of infested material, namely, fallen and hanging dry 

 squares, and fallen and hanging dry bolls. 



A few words of explanation of these tables are necessaiy in order 

 to show what is meant by the different classes of mortality. It has 

 been found that a large number of stages are destroyed as eggs or 

 young larvae by the proliferation of the plant tissues. At the time 

 of the examination for mortality of the weevil, all evidence of the 

 weevils destroyed in these stages has disappeared; consequently the 

 percentages of mortality given in the following tables are the per- 

 centages of stages found which are killed by the causes enumerated, 

 and the mortality from proliferation is entirely ignored. 



Table II. — Monthly mortality of the boll weevil due to insects in fallen squares. 



