November 4, 1904.] 



SCIENCE. 



611 



most of their customers, but it would put them 

 to some extra expense and inconvenience if 

 government purchases are made in the best 

 market. Whether this international system 

 should be exclusively metric is a matter of 

 policy requiring careful consideration. The 

 yard may be lengthened to equality with the 

 meter, or the meter may be lengthened to 

 forty inches, or many British units may be 

 discarded and some metric units may be sub- 

 stituted for them, while some British units 

 are retained. In any case the change, what- 

 ever it be, must tend toward unification and 

 simplicity. It must necessarily cause initial 

 increase of confusion, which will pass away 

 without unreasonable delay in great commer- 

 cial centers. Outside of such centers the peo- 

 ple may be expected to hold on to their old 

 habits; and in the remote rural districts hun- 

 dreds of years may be insufficient to bring 

 about uniformity. The essential desideratum 

 is definiteness in value and simplicity in 

 mutual relation among the units adopted. The 

 mere nomenclature is of subordinate impor- 

 tance. Old names will certainly be retained 

 by the masses even if values are modified, just 

 as a dozen different values existed a few years 

 ago for what was called foot, fuss, pied, etc. 

 The change in values will be much easier for 

 the masses if the old names are retained by 

 legal provision; but this is a matter for which 

 there is plenty of time. The Archimedean 

 lever is indeed unknown, but even the English 

 inch has been ' moved ' in the past and Mr. 

 Halsey's ' impossibilities ' are no greater than 

 what have been gradually overcome in the 

 past and what may be gradually overcome in 

 the future. 



W. Le Conte Stevens. 

 Washington and Lee UlsrivEEsrry, 

 October 3, 1904. 



PROFESSOR WILLIAM MORTON WHEELER ON THE 

 KELEP. 



In Science of September 30 (p. 437) Pro- 

 fessor William Morton Wheeler has discussed 

 the introduction into the United States of the 

 kelep or Guatemalan cotton-protecting ant, 

 and has reached decidedly adverse conclusions. 

 Every new proposition must, of course, run 



the gauntlet of criticism, scientific and un- 

 scientific. Professor Wheeler claims special 

 ' liberty to comment ' because of ' exceptional 

 opportunities,' but he nevertheless disregards 

 several facts which might have mitigated the 

 confidence of the prophecy. 



It becomes apparent that the Poneridffi with 

 which he is acquainted must be very different 

 from the kelep. After observing colonies of 

 Ectatomma and Odontomachus, both in na- 

 ture and in captivity, I am ready to follow 

 Mayr and Ashmead in assigning these genera 

 to separate families, as unlike, indeed, as rats 

 and rabbits. Whatever may be true of other 

 Poneridse or Odontomachidse, it seems that 

 the species of Ectatornvfia are widely dis- 

 tributed, enterprising ants. The kelep, in- 

 stead of being a rare ' archaic ' curiosity, is 

 decidedly the dominant and most abundant 

 insect of the Guatemalan cotton fields. The 

 colonies, too, are several times as large as 

 supposed by Professor Wheeler. They con- 

 tain, usually, between 200 and 300 individ- 

 uals, instead of from 40 to 50. There are 

 seldom less than 100, and sometimes 400 or 

 more. 



The adaptability of the kelep is further 

 shown by its association with the cotton for 

 the sake of its nectar, as well as by its skill 

 in stinging the boll-weevil. It is true, as Pro- 

 fessor Wheeler says, that there are other pug- 

 nacious ants which ' attack ' boU-weevils (or, 

 for that matter, anything else which comes in 

 their way), but they let them go again, and 

 have no standing as 'destroyers.' To sting, 

 disable, carry off, dismember and consume the 

 pest, is still the unique distinction of the 

 kelep. 



Like some editors of newspapers Professor 

 Wheeler will not be satisfied with the ants 

 unless they absolutely exterminate the weevils, 

 'chase them into the Gulf of Mexico,' etc. 

 The planters would probably be grateful, how- 

 ever for an addition of even ten per cent, to 

 their crop— which illustrates the difference of 

 standpoints. That the keleps make a regular 

 practise of killing weevils renders them of 

 distinct agricultural interest; the question is 

 no longer whether they are useful, but whether 

 we can get enough of them. Just how effi- 



