54 



THE MEXICAN COTTON-BOLL WEEVIL. 



Tablk XIX. - Ige of the boll weevil at beginning of oripos-ition. 



tdult. 



Place. 



Date first egg. 



Number 

 of fe- 

 males. 



Number 

 weevil 



days. 



Average 

 age. 





Victoria, Tex 



June 16-10 



27 

 11 



16 

 8 

 9 

 4 



10 



150.0 



44.0 

 106. 



116.0 

 56.0 

 73.0 







Talliilah, La 



July 14-19 



6.00 



July 29-31, 1910 



Aug.] 



Sept 1 9 L902 



do 



.....do 





6 29 



Aug. 21 



6.66 



Sept. H.-17 



9.06 





Talliilah, La 



Sept. 18-Oct.8 



Oct. 16 



12.89 



L902 





14.00 



Nov 9-11 1902 



do 



NOV. 10-19 



7.30 





June 16-Nov. 19 







92 



683.5 



7.40 









EXAMINATION OF SQUARES BEFORE OVIPOSITION. 



In the course of a great many observation upon oviposition it was 

 Pound that females almost invariably examine a square carefully 

 before they begin a puncture for egg deposition. This examination 

 is conducted entirely by means of senses located in the antenna 1 and 

 not at all by si^ht. In fact, the sense of sight appears to be of com- 

 paratively small use to this weevil. In regard to the actual time 

 spent in the work of examination before beginning a puncture, over 

 sixty observations are recorded. These show that the average time 

 is over t wo minutes. This examination of squares is made by females 

 only when they intend to oviposit. Males have never been observed 

 acting in this way, nor do females generally do so when their only 

 object is to feed. 



SELECTION OF UNINFESTED SQUARES FOR OVIPOSITION. 



The sense by which the weevil examines the squares frequently 

 enables it to detect an infested condition when no external sign is 

 visible. Females sometimes refrain from placing eggs in squares, 

 even when they are apparently searching for a place to oviposit and 

 anxious to do so. The acuteness and accuracy of the preliminary 

 examination is well shown by the fact that when provided with more 

 squares than they have eggs to deposit they do not often place more 

 than one e^g in a square. Where a totally infested condition is 

 reached, as is frequently the case in the field, no choice between in- 

 fested and uniniested squares could be exercised, and then, unless the 

 female happens to be in a condition to refrain from oviposition, she is 

 forced to deposit more than one egg in a square. Tabic 1 XX illus- 

 trates the distribution of egg and feeding puncture as collated from 

 many records. 



Table XX. Selection of squares and relation of feeding to oviposition of the boll weevil. 



Place and time oi 

 obsexval ion. 



Total 

 squares 

 attacked. 



Squares with 

 1 egg each. 



«2r 1 s «^ 



T/gS' 'eedmgpunc- 



Squares fed on 



only. 



Num- 

 ber. 



Percent 



of total 

 squares. 



Num- 

 ber. 



Per cenl 



of total 

 squares. 



Num- 

 ber. 



Per cent 

 of total 



squares. 



Num- 

 ber. 



Per cent 

 of total 

 squares. 



In laboratory, 1902 



In field, 1902 



630 



151 

 560 



477 



51 



317 



531 

 413 



7.".. 7 



37. o 

 55.9 

 51.2 

 15.4 



19 

 33 



83 



415 







3.0 



21. s 

 14.8 

 40.0 

 0.0 



24 

 46 

 50 

 90 

 1,832 



3.8 

 30.4 

 8.9 

 8.6 

 68.4 



lid 



Hi 



110 







434 



17.4 

 10.5 



in field 



19 6 



in field, 1906 



In field, 1907 



0.0 

 16.2 







.1 



5,056 



1,794 





550 





2,042 





670 





Mage 



35.4 



10.8 



40.3 



13.2 









