26 WEEVIL-RESISTING ADAPTATIONS OF COTTON. 



while 7<'» per cent of the plants of the Kekchi cotton were favored with 

 kelep nests. This apparent preference may be somewhat exaggerated, 

 perhaps, in view of the fact that the plants Avere often farther apart 

 in the rows of the Kekchi cotton, the seed having germinated very 

 irregularly. Moreover, the superior attraction of the Kekchi cotton 

 for the keleps may not have consisted entirely in the greater hairiness 

 or the more abundant nectar. The compact foliage and spreading 

 lower branches of the Kekchi cotton give greater protection from the 

 midda}^ sun, which the keleps utilize by greater activity in the middle 

 of the day. 



AVith the Sea Island varieties it seemed obvious, however, that the 

 smooth stems, more open habit, and smaller supply of nectar result in 

 distinctly less attention from the keleps. From 9 or 10 o'clock on hot 

 days they foraged very little, and seemed to have quite disappeared 

 from these varieties, though still to be found in considerable numbers 

 on the stems of the Upland varieties and most of all on the Kekchi 

 cotton, which appears especially adapted for the comfort and con- 

 venience of the keleps. 



It was noticed, however, that the keleps went much more often into 

 the involucres of the Sea Island and Egyptian varieties than into those 

 of the Kekchi cotton, for the simple reason, probably, that they can 

 get in more easily. 



In the latter part of the season, after the weevils had gained a foot- 

 ing in this field. Professor Pittier noticed a very decided preference 

 on their part for the Egyptian varieties, though it seems certain that 

 this type of cotton had never been planted in the country before. The 

 partiality of the weevils might be explained, perhaps, on such grounds 

 as the relative absence of the keleps, and also the ease of access to the 

 buds of the Egyptian cotton allowed by the more open involucres. 

 However, a slight change of food or of conditions of growth is often 

 a distinct advantage to plants and animals, so that a direct preference 

 for a new variety as food might reasonably be expected, and similar 

 instances are known. 



The greater hairiness of the stems and the presence of the keleps 

 may also explain why the weevils in Guatemala were seldom seen 

 walking about on the cotton plants as they do in Texas. On the 

 other hand, they take to wing very readily and seem to prefer to 

 alight in the open flowers, the only places on the cotton plants where 

 they are safe from the keleps. 



The petals are so smooth that the keleps seldom descend into the 

 flowers, and when they do sometimes appear to be unable to climb 

 out. The petals of the Sea Island sorts are smooth even on the mar- 

 gins, sometimes entirely so, while those of the Upland varieties are 

 fringed with fine hairs well up on the sides, if not all the way round 

 the apex. 



