THE CONCHUELA. 



55 



DESTRUCTIVENESS. 



INDIVIDUAL CAPABILITIES. 



As a basis for determining the amount of damage done to cotton 

 bolls by individual conchuelas an examination was made on July 

 17, 1905, of 104 bolls upon which one or more adults were observed 

 feeding. These bolls were opened and the number of punctures 

 found on the inside of the carpels was recorded. One hundred bolls 

 showed positive injury, and the remainder did not show enough 

 discoloration to justify their inclusion with those believed to be 

 ruined, although the two smaller ones would very likely have failed 

 to mature if left on the plants. These 4 bolls were in diameter 

 approximately one-half an inch, three-fourths of an inch, one and 

 one-eighth inches, and one and one-fourth inches, and showed on the 

 inner side of the carpels, 2, 5, 19, and 32 punctures, respectively. 

 The results of the examination of the damaged bolls are summarized 

 in the following table: 



Table 'X.'XN .—Results of examinations of 100 bolls upon which one or more specimens 

 of the conchuela had been observed feeding in the field. 



Approximate 

 diameter. 



Num- 

 ber. 



Badly 

 damaged. 



Slightly 

 damaged. 



Total 

 number of 

 punctures. 



Average 

 number of 

 punctures 



per boll. 



Maximum 

 number of 

 punctures 

 per boll. 



Minimum 

 number of 

 punctures 

 per boll. 



Inches. 



1 



7 



14 



15 



23 



28 



8 



4 







7 



10 



10 



21 



20 



5 



2 



1 

 



4 

 5 



2 

 8 

 3 



2 



3 



119 

 266 

 420 

 1,150 

 1,484 

 504 

 172 



3 



17 

 19 

 28 

 50 

 53 

 63 

 43 



3 



34 

 34 

 41 



88 

 141 

 136 



68 



3 

 15 



3 



9 

 35 

 22 



8 

 28 



I 



1 



7 



1^ 



1| 



li 



If 



Totals and sum- 

 mary 



100 



75 



25 



4,118 



41 



141 



3 





Data have now been given from which we may calculate approxi- 

 mately the amount of damage that a single conchuela is capable of 

 doing. It has been shown that in cotton fields in midsummer each 

 insect spends on an average about 78 per cent of its time feeding on 

 cotton bolls or in round numbers about 1,100 minutes per day. At 

 the rate of 1 puncture for each 20 minutes while feeding, 55 punctures 

 per day would be made by each adult of these insects. The average 

 number of punctures (41) in the damaged bolls referred to in Table 

 XXV is equivalent, therefore, to the number one adult may make 

 in about three-fourths of a day. 



Estimates based upon actual counts and examinations in various 

 parts of Ceceda A, taUa 14, places the number of bolls about the 

 middle of July in the entire tahla at a little over 2,500,000 and the 

 number damaged by bugs at a little more than 1,125,000. Other 



