310 



SCIENCE. 



[N. S. Vol. XX. No. 505. 



in bibliographic work, but also in all cases 

 where there is no clear advantage in favor 

 of the more cumbersome system, might have 

 the support of quantitative data I have chosen 

 ten well-educated, and in most cases scienti- 

 fically trained individuals, and determined 

 for each the time necessary for the writing 

 of the Roman and the Arabic numerals from 1 

 to 100 and the number of errors made, also the 

 time necessary for the reading of the Eoman 

 and the Arabic numerals from 1 to 100 when 

 they were irregularly arranged so that the 

 reader did not know what order to expect. 

 In all cases the number of errors made un- 

 consciously was recorded. These measure- 

 ments furnish the following startling aver- 

 ages: It takes three and one third ^ times as 

 long, to write the Soman numerals from 1 to 

 100 as the Arahic, and the chance of error is 

 twenty-one times as great; it takes three times 

 as long to read, dhe Boman numerals from 1 

 to 100 as the Arahic, and the chance of error is 

 eight times as great. 



In case of a quick and accurate mathema- 

 tician, whose familiarity with the Roman sys- 

 tem surpassed that of most of the individuals 

 tested, the results were: time for writing 

 Arabics, 107", errors, 0; time for writing 

 Romans, 357", errors, 5; time for reading 

 Arabics, 62", errors, 2; time for reading Ro- 

 mans, 131", errors, 5. For one well-trained 

 scientist, who has cause to use the Roman 

 system almost every day, the number of errors 

 in the rapid reading of the Romans was 15 ! 



These figures certainly indicate the desira- 

 bility of using the Arabic system wherever 

 there is no urgent need for the simultaneous 

 use of two or more systems of numerals. Even 

 if there were no saving of time and strain 

 by the avoidance of the cuiubersome Roman 

 symbols, the far greater accuracy gained by 

 the use of the Arabic system should at once 

 settle the matter for all scientists. 



ROBEET M. YeEKES. 



Harvard Tjniversitt. 



[The best usage in bibliographic work is to 

 use heavy-faced Arabic type for the volume 

 number. The number should be underlined 

 in the manuscript with a waving line, and it 

 will then be set in heavy-faced or block type 



by the printers. This usage we think orig- 

 inated in American botanical publications. 

 The volume number in heavy-faced type is 

 followed by a colon and then the page num- 

 bers are given in ordinary type. The date 

 or year then follows after a period, though we 

 should suppose that a comma would be better. 

 The International Catalogue of Scientific Lit- 

 erature has adopted the heavy-faced type for 

 the volume number; this is followed by a 

 comma and the year, the page numbers being 

 then given in parentheses after another com- 

 ma. We think that the American usage is 

 the better and should be pleased if our con- 

 tributors would follow it. The pages of the 

 International Catalogue are disfigured by 

 hundreds of thousands of needless parentheses 

 and periods. — Ed.] 



SPECIAL ARTICLES. 



PUPATION OF THE KELEP ANT. 



The larva; of ants share with those of but- 

 terflies and moths the habit of spinning 

 cocoons in which their transformation to the 

 adidt form takes place, though not all the ants 

 make cocoons. Lubbock states that ' as a gen- 

 eral rule, the species which have not a sting 

 spin a cocoon, while those which have are 

 naked,' the implication being, apparently, that 

 less protection is required by species having 

 stings with which to defend themselves. It 

 would seem, however, that the absence of the 

 cocoon rather than its presence is to be looked 

 upon as the adaptive character. The keeping 

 of the insects from drying out during the in- 

 active period of transformation is probably a 

 more important general function of cocoons 

 than that of protection against enemies, but 

 the moist underground chambers and compact 

 social organization of the ants have rendered 

 cocoons unnecessary, and in many genera they 

 have been dispensed with. 



The family Poneridse to which the kelep* 



* The kelep has been identified by Dr. Ashmead 

 and Mr. Pergande as Ectatomma tuberculatum 

 Oliv., a species widely distributed in tropical 

 America, including Mexico, and hence the more 

 likely to become established in Texas. It does 

 not follow, however, that the instinct of attacking 

 the boll-\\'eevil is possessed in an equal degree by 



I 



