62 



NATURAL CONTROL OF THE COTTON BOLL WEEVIL. 



of weevil stages found in this class of forms bein<j: somewhat more 

 than 60 per cent of the total. Eastern Texas, southern Texas, and 

 western Louisiana seem to have profited most by the work of the ants 

 in fallen squares, and these same sections show the highest percentages 

 of ant work in fallen bolls, as might naturally be expected. 



The wide diversity of conditions under which the ants successfully 

 attack the weevil is another one of the encouraging features sho\\Ti by 

 this work. It proves in a very reassuring way the general (listri))ution 

 of this species of Solenopsis and their activity in destroying weevil 

 stages in every class of forms and in all parts of the infested area. 

 The value of the work which they do in restraining the weevil multi- 

 plication can not be estimated. Their work henceforth will l)e more 

 fully appreciated and a careful stud}" will be made of the life history 

 of the species and of the possibility of producing an increase in its 

 efficiency. 



SECTIONS PROFITING MOST BY NATURAL CONTROL. 



Still another arrangement of this same series of results will show 

 most plainly a comparison of the total mortality in the four classes of 

 forms for each of the six sections into which the localities have been 

 grouped. In Table XIII are sho^\^l the general results of the 

 examinations. 



Table XIII.— Comparison of total mortality results according to section. 





Total 

 forms 

 exam- 

 ined. 



Weevil stages alive. 



Weevil stages dead ' 



Mortalitv from heat. 



Section. 



I.arva. 



Adult. 



from heat or drj'ing. etc., by stages. 





l'"P^-| Pres- 

 ent. 



Em- 

 erged. 



Larva. Pupa.] Adult. 



! 1 



Larva. Pupa. Adult. 



Western Louisiana . . 



Eastern Texas 



Southern Texas 



Central Texas 



Northeastern Texas '. 

 Southwestern Texas . 



10,999 

 12, 933 

 37.080 

 16, 724 

 7.172 

 2,048 



1 1 1 



576 672 ! 365 i 1,070 

 1,374 883 259 I 397 

 2,311 ; 1,665 ' 1,033 i 1,407 

 865 1 923 ; 462 ' 686 

 430 376 258 , 334 

 396 126 30 ; 48 



1 



: ! 

 293 1 138 i 105 

 492 ' 76 ' 24 

 4,812 603 155 

 820 131 105 

 137 77 32 

 62 3 3 



Perct. P.ct. Perct. 

 50.9 20.5 7.3 

 35.8 8.6 3.7 



67.6 26.6 6.0 



48. 7 12. 4 8. 4 

 24.2 17.0 5.1 



1.6 2.4 3.8 





86,956 



5,952 



4,645 i 2,407 1 3,942 



! 1 



6,616 1,018 ! 424 



! 1 



52.6 18.0 6.3 





Killed by heat 

 or drying. 



Killed by ants. KiM-^^y ! ^^^^^ ' n>^ 

 Total Tier cent .9^ ^9 



Section. 



Num- 

 ber of 

 stages. 



Per cent 

 of total 

 stages 

 found. 



Number 

 of stages. 



Per 

 cent of 1 Num- 

 total ber of 

 stages stages, 

 found. 



Pp_ number of mor- "'""'" 

 cent of «^ ^^'^«^'*1 *^^^ty ?eni 



H ss ^ ^ 



found. 1 causes, t^lity. 



Western Louisiana . . 



Eastern Texas 



Southern Texas 



Cent ml Texas 



Xortheasteni Texas . 

 Southwestern Texas. 



526 

 592 

 5, .570 

 l,0.^6 

 246 

 68 



10.3 

 11.1 

 28.3 

 18.2 

 11.1 

 8.1 



1,526 

 1,465 

 5,921 

 1,137 

 376 

 117 



29.9 156 

 27.4 155 

 30.0 811 



19.8 443 



16.9 86 

 13.9 34 



3.0 1 5,117 1 43.2 3 

 2.9 1 5,339 ! 41.4 4 



4.1 ! 19,674 1 62.6 1 



7.8 1 5,799 1 45.5 2 



3.9 2,222 31.9 5 

 4.0 840 26.0 6 





8,ft58 i 20.7 1 10,542 



27.0 , 1,685 



4.3 . 38,991 1 52.0 



