78 



before they Trill begin a puncture for egg deposition. This examina- 

 tion is conducted entirely by means of senses located in the antenna? 

 and not at all by sight. In fact, the sense of sight appears to be of 

 comparatively small use to this weevil. 



In regard to the actual time spent in the work of examination before 

 beginning a puncture GO observations were 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 OVIPOSITIOX. 



So unerring is the sense by which examination is made that in a 

 few cases it was able to discover an infested condition no external sign 

 of which was visible to the writer's ej^e. A female which was under 

 close observation examined in the usual manner the square given her, 

 but though evidently searching for a place to oviposit and anxious to 

 do so, she plainly objected to placing an egg in that particular square. 

 The writer again examined the square carefully, but found no sign of 

 infestation and replaced it in the observation cage. Again the female 

 made her usual careful examination and still she plainly refused to 

 oviposit. Upon removing the covering from the square it was found 

 to contain an egg^ but the puncture made in depositing it had healed 

 so smoothly that it had thrice escaped observation. The same female 

 was then given two squares, one of which was known to be infested, 

 the latter being placed nearer her. She examined it caref ully, then 

 left it, and went at once to the clean square, in which, after the usual 

 examination, she deposited an egg. 



The acuteness and accuracy of the preliminary examination is also 

 well shown by the fact that when provided with more squares than 

 they have eggs to deposit they rarely place more than one egg in a 

 square. It was frequently found, however, that when a female depos- 

 ited just as many eggs as there were squares present she would place 

 two eggs in one_and then make only feeding punctures in the remain- 

 ing square. 



The observations were made upon a large number of females; so 

 there can be no doubt that the habit of selection is general. The 

 conditions provided in these experiments were intended to resemble 

 those existing in a slightly infested field early in the season, where each 

 female could easily find an abundance of clean squares in which to 

 deposit her eggs. Therefore only those cases were recorded in which 

 the number of squares present equaled or exceeded the number of 

 eggs deposited. Where a totally infested condition is reached no 

 choice between infested and uninfested squares could be exercised, 

 and then unless the female happened to be in a condition to refrain 



