THE TEXTILE PLANTS 63 



have not been exterminated in Guatemala, 

 although the kelep has there imposed a very 

 important check on their increase. 



It is urged, however, that additional protection 

 from the boll weevil must be sought through such 

 development of the cotton plant itself as will 

 make it resistant to the attacks of the insect. The 

 authorities of the Department of Agriculture 

 have observed that in the cotton plants of Guate- 

 mala, where the weevil is native, the buds do not 

 always drop off after being penetrated, and that 

 the young bolls continue to develop. 



It was found on examination that such resist- 

 ance was due to the actual growth of new normal 

 tissue into the cavity eaten out by the weevil 

 larva, with the result uniformly fatal to the 

 larva itself. It appears that the larva in its 

 younger stages subsists entirely on the highly 

 organized food material to be found in the pollen 

 grains of the unopened cotton flower. The new 

 tissue formed by a mere swelling or proliferation 

 from the central column of the flower is watery 

 and innutritious, and may starve the larva to 

 death even if it does not act as a poison. 



Here, then, is a method by which the cotton is 

 able to offer effective resistance to the weevil. 



It is suggested that if a variety of cotton could 

 be developed in which the tendency to the growth 



