NA SOUTHERN 



ARizcna 



NORTHERN 



VALPARAISO 



MTS., 

 ZACATECAS 



SANTA ROSA, MEXICO 



GUANAJUATO MORE LOS 



OAXACA 



DURANSO OKLAHOMA VIRSINIA 



COAHUILA KANSAS WEST VIRGINIA 



NUEVO LEON 



¥- 



NUMBER Of SPECIMENS 



IN SAMPLE 

 OBSERVED RANGE 

 OBSERVED MEAN 



. 2 STANDARD DEVIATIONS 

 ON EITHER SIDE OF MEAN 



17. — Greatest length (in 

 (lower »et of figur 



mm.) o( ikulll o( •pccimeni of PImluj lomstndii (upper •et of figurn) and Plia«t 

 <), arranged in geographic sequence from northwest to south, thence lo northeast. 



