862 



SCIENCE. 



[N. S. Vol. XIX. Xo. 492. 



association with their elders. Where now are 

 the teachers and exemplars? 



Theo. Gill. 



price of the reports of the harkiman 

 expedition. 

 I DESIRE to correct an error in my review of 

 volumes three and four of the Harriman Ex- 

 pedition, published in the preceding number 

 of Science (May 2, 1904). As I have been 

 informed, the price which I quoted from a 

 trade-list of the publisher applies to volumes 

 one and two of the series and not to subse- 

 quent volumes. The price of volumes three 

 and four, the ones reviewed, is $5.00 per 

 volume. Israel C. Eussell. 



SPECIAL ARTICLES. 



AN ENEMY OF THE COTTON BOLL WEEVIL. 



Specimens of the cotton boll weevil were 

 obtained in eastern Guatemala in 1902, during 

 a visit made to that country in order to study 

 the culture of coffee and rubber, for the United 

 States Department of Agriculture. The in- 

 sects, which were collected on the request of 

 the Division of Entomology, were not found 

 on the cotton cultivated by the Indians, but 

 were very common in the flowers of the tree 

 cotton growing spontaneously near a native 

 house, a short distance from the cotton field. 

 The beetles were secured in a rather inac- 

 cessible part of Alta Vera Paz, seldom visited 

 by naturalists or other travelers. It lies be- 

 tween Cajapon and Sepacuite, and is inhabited 

 only by primitive Indians and a very few 

 Spanish-speaking ' natives ' of mixed blood. 



The Indian variety of cotton seemed very 

 small and unpromising, only one or two bolls 

 being borne on a plant ; it seemed very strange 

 also that so small a variety should be planted 

 while the large tree cotton was so ready at 

 hand. It was learned, however, from Mr. 

 Kensett Champney, who has a most thorough 

 acquaintance with the agricultural habits of 

 the Indians, that this was the only variety of 

 cotton planted by them in this district, and 

 the one exclusively relied upon to furnish 

 material for their native fibers. The absence 

 of the weevils from the small Indian cotton 

 was reported when the specimens of the beetles 



were brought back to Washington, but the 

 diminutive size of the plant seemed to forbid 

 any recommendation of profitable utility in 

 the United States. 



Later on, with the increasing acuteness of 

 the boll weevil question and the voting of a 

 special appropriation by Congress for the 

 study of means of protection against its 

 ravages, the existence of a variety of cotton in 

 Guatemala which seemed not to be subject to 

 the attacks of the boll weevil was recalled, and 

 it seemed to the authorities of the Bureau of 

 Plant Industry that every clue should be fol- 

 lowed up. The Secretary of Agriculture au- 

 thorized an investigation of the Indian cotton 

 of Alta Vera Paz, to ascertain whether it 

 possessed, in reality, any quality enabling it 

 to resist the boll weevil, or to leam other 

 causes of its immunity from the attacks of the 

 insect. The custom of the Indians to plant 

 their crops every year in tracts of land recently 

 cleared by burning suggested an alternative 

 possibility that if not actually resistant to the 

 weevil the cotton might have an almost equally 

 valuable tendency to quick growth, thus en- 

 abling a crop to be obtained before the weevils 

 had time to become injuriously numerous. 

 The importance of securing early varieties 

 has been emphasized as the result of the in- 

 vestigations of the boll weevil in the United 

 States. 



In this part of Guatemala the present sea- 

 son has been much more rainy that that of 

 1902, and the cotton is much larger. Well 

 grown plants bring to maturity from ten to 

 twenty bolls of fair size, and even more. A 

 thorough search shows that the weevil is pres- 

 ent and able to injure the cotton, but reveals 

 also an active enemy which keeps it in check. 

 This is a large reddish brown ant which is 

 attracted to the cotton by the food which it 

 secures from three sets of extra-floral nectaries. 

 Each leaf has a nectary on the under side of 

 the midrib, from one to two centimeters from 

 the base. Each of the large bracts of the in- 

 volucre has a circular or broadly oval nectary 

 close to the stem, and there is a third series 

 of three nectaries at the base of the calj^, be- 

 tween the pair of small bracts alternating with 

 tlie larger divisions of the involucre, of which 



