54 THE MEXICAN COTTON-BOLL WEEVIL. 



Table XIX. — Age of the boll weevil at beginning of oviposition . 



EXAMINATION OP SQUARES BEFORE OVIPOSITION. 



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

 found 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 antennae and 

 not at all by sight. 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 two 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 egg in a square. Where a totally infested condition is 

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

 fested and uninfested 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. Table 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. 



