SUMMARY AND CONCLUSIONS. 75 



The proportion of clear to cloudy days and the relative rainfall 

 seem to influence in considerable degree the effectiveness pi high 

 temperatures. 



Comparison of mortality records in localities infested for not 

 more than two years with those in localities infested for from three 

 to ten years shows a total mortality averaging about 10 per cent 

 greater in the section longer infested. This increase was due princi- 

 pally to the greater effectiveness of heat and parasites, while in the 

 recently infested area ants were exceptionally effective. The princi- 

 pal reasons for these differences were probably the more moist cli- 

 mate and the more abundant ant distribution in the recently infested 

 area. 



Nearly 70 per cent of all mortality found from heat or drying 

 occurred during the larval stage. The ratio of mortality percent- 

 ages in each weevil stage from heat is: Adult 1, pupa 3, larva 9. 

 An early shedding of infested forms is very desirable. 



Whatever spacing may have been found advisable where weevils 

 were not present, these records prove the general soundness of the 

 recommendation for increasing the space allowed each plant where 

 the weevils are abundant. Central Texas shows the high average 

 mortality of 21.8 per cent by parasites in hanging squares, 8.4 per 

 cent in hanging bolls, and 5.7 per cent in fallen squares. Owing 

 to the small number of observations made in southwestern Texas, 

 western Louisiana should really be ranked first, with 39.4 in average 

 percentage of total mortality among hanging dried bolls, while cen- 

 tral Texas is second, with 28.8 per cent. Among hanging dried 

 squares central Texas stands first, with 65.4, and western Louisiana 

 second, with 61.3 per cent. Among fallen bolls eastern Texas ranks 

 first, with 50 per cent mortality, and western Louisiana second, 

 with 33.4 per cent. In eastern Texas alone did the number of fallen 

 bolls examined exceed the number of fallen squares. Among fallen 

 squares southern Texas has a long lead in total mortality, with 70.7 

 per cent, as compared with central Texas, with 50 per cent. The 

 high percentage found in this class is based upon much the largest 

 series of examinations made for any class in any section, and the 

 figures are therefore exceptionally reliable and significant. 



In degree of benefit from natural control, the six groups of locali- 

 ties rank as follows in average percentage of total mortality 



Per cent. 



Southern Texas (i'2. (i 



Central Texas 15. 5 



' Western Louisiana 43. 2 



Eastern Texas 1 1 . I 



Northeastern Texas :» 1 . !» 



Southwestern Texas 26. 



