Show scientists find locusts are of 2 Di distinct kinds there are two races of the periodical cicada the seventeen year race and another that appears every 13 years scientists have found no differences in the two except that one remains underground in the larva sand pupa stages tour four years longer than the other every year is locust year in some part of the country there are 17 different broods of the 17 year race and thirteen cen broods of the 13 year race writes a correspondent in the chicago tribune the broods have been catalogued cataloguer catalo gued by roman numbers broods nos I 1 to 17 compose the 17 year race the 13 year race is numbered from 18 to 30 broods are thus easily distinguished there is overlapping of the territories occupied by the two races and also by the different broods in some sections however the locusts only appear at 13 or 17 year intervals indicating the presence of only one brood the periodical cicadas are not found in the western part of the united states they live maidl mainly y in the wooded regions from the atia allan tic coast westward to central kan kai sas |