THE PROGRESS OF SCIENCE. 



189 



at present engaged in mapping the 

 spectra in the ultra-violet region. 

 Chemists have agreed to accept an 

 element only when a definite atomic 

 weight and characteristic spark spec- 

 trum are had. To be sure such im- 

 portant observations require verifica- 

 tion in the hands of others as well. 



THE INSECT ENEMIES OF 

 COTTON. 



That the high price of cotton is 

 partly due to the abundance of certain 

 insect pests in the south is strikingly 

 shown by the two maps, which we 

 reproduce, showing the distribution in 

 Texas of two of the more important 

 insect enemies of cotton. The boll- 

 worm has long been known as injurious 



to cotton, corn and other crops, in 

 foreign countries as well as in the 

 United States. The Mexican cotton 

 boll weevil, at present the most serious 

 menace to cotton culture, has spread 

 northward from Mexico during the 

 past ten years, until now it occupies 

 tlie greater part of the Texan cotton 



1 belt, and has entered Louisiana. Both 

 of these insects live within the boll or 

 carpel of the cotton plant; and at pres- 

 ent there is no way of combating them 



I save by cultural methods. The gov- 

 ernment has appropriated a consider- 

 able sum of money for an investiga- 

 tion of these insects, and a number of 

 scientists, under the Department of 

 Agriculture, are now at work in Texas 



j and Louisiana. The present status of 



Map showing distribution of cotton boll weevil in the United States in 1903. The heavy line 

 ndicates the limit of the region in which the weevils have multiplied 10 such an extent as to 

 be found in all cotton fields; the remainder of the shaded portion indicates the region in 

 which colonies are known to exist. 



