102 



The National Geographic Magazine 



Photo by E. R. Warren 



field mouse; 



When numerous field mice do enormous damage to crops (see page 92) 



zone maps of the utmost practical use — 

 and a very important one — is to accom- 

 pany the maps with a list of the fruits, 

 grains, and vegetables best suited to each 

 zone. Thus the necessary experimenta- 

 tion on the part of the farmer is reduced 

 to a minimum. The farmer who wishes 

 to find land where a certain crop may 

 be planted with success, or the emigrant 

 in search of conditions similar to those 

 he is familiar with at home, has only to 

 refer to the zone maps and to the lists 

 •connected therewith. 



A small scale zone map of the United 

 States has been completed, with lists of 

 the farm products most likely to thrive in 

 the several belts. While for general pur- 

 poses this map is very useful, it is by no 

 means detailed enough to give all the in- 

 formation the farmer or emigrant in 

 search of a new location desires. It is 

 the present purpose to survey each im- 

 portant agricultural state with sufficient 

 detail to enable life and crop zone maps 

 to be published, with lists of the crops 



specially adapted to the several parts of 

 the respective states. 



Such crop and zone maps are useful in 

 still another field. At the present time 

 the whole world is being searched by 

 specialists for fruits and plants, suited to 

 the conditions that prevail in our own 

 country. The usefulness of such maps 

 as a guide to the most favorable localities 

 in which to test the value of these foreign 

 importations can hardly be overestimated. 



Noxious insects also in their dispersal 

 over the country follow the same faunal 

 belts, as do also many of the dis- 

 eases of domestic stock and even of man. 

 Yellow fever, the germs of which are 

 now known to be distributed by a mos- 

 quito, has been shown to be limited to 

 a transcontinental belt the boundaries of 

 which were laid down by the Survey 

 nearly twenty years ago. 



Curiously enough the regions formerly 

 occupied by particular tribes of Indians 

 correspond in a general way with these 

 same life zones, as was pointed out by 



