50 WEEVIL-RESISTING ADAPTATIONS OF COTTON. 



The burrow inii' of the weevil relieves this pressure at one point, and 

 may thus furnish the exciting cause of the rapid growth in this direc- 

 tion of the tissue of the staniinal tube. 



It seems not improbable that a relation will be found between the 

 method of culture and the extent and frequency of proliferation. 

 Open-field conditions, with much bare ground about the plants, Avould 

 increase the daily exposure of heat and dry air, and this would con- 

 duce to the wilting of the punctured squares, which might then be 

 expected to flare and fall oif instead of remaining to proliferate. The 

 result of weevil work in our open-culture plots was obviously differ- 

 ent from that in the more crowded cotton fields of the Indians. On 

 the widely separated plants the squares often fell off and permitted 

 the larva? to develop, as in Texas, except that there was still a distinct 

 tendency on the part of the larva^ to attack the pistil and ovary first, 

 before eating out the pollen. 



PUOLIFERATION IN OTHER VARIETIES. 



Proliferation is by no means confined to the Kekchi cotton, but 

 probably occurs, occasionally at least, in all the Upland and Sea 

 Island varieties. A noteworthy Guatemalan Sea Island cotton was 

 found by Mr. Kinsler in the aldea of San Lucas, a few miles from 

 Secanquim." Both the buds and the bolls afforded fine examples of 

 effective proliferation. Even the Egyptian varieties showed a dis- 

 tinct ability in this direction. In one instance no less than 17 of 23 

 punctured squares of Jannovitch had proliferated, and 15 cases 

 seemed to have been effective. 



Proliferation ceases to occur when the bud has become too large. 

 The anthers are no longer so closely packed together and the tissues 

 of the staminal tube are too nearly mature. By that time, however, 

 the style may be sufficiently developed to furnish adequate food. 

 It is well known, however, that the period of development of the 

 weevil larva^ may be greatly prolonged, and this would seem likely 

 in the present instance, since the tissues of the styles must be less 

 nutritious than the pollen. The delay also would be advantageous, 

 since it would i)ermit the young boll to become larger. 



a This variety is peculiar in having about half of each seed covered only with a 

 very fine, short, bright bluish-green lint. The upper half bears the long white 

 fiber, and is smooth and l)laclv when this has been removed. Some of the 

 plants had excellent crops of bolls, mnisually uniform in size and ai)parent age, 

 as though the habit of seasonal fiowerlng were well accentuated. The variety 

 is evidently perennial and grows to a height of from 6 to S feet, but on the 

 other plants the leaves, flowers, and bolls were much reduced in size. The 

 plants were all occupied by small black ants. On some of them no weevils nor 

 any indications of weevil injury were fomid, but others only a few" rods awaj' 

 were badly infested, 



