Analysis of Hetebogeneity in the Population 



299 



In the first census of 1904 the population showed a condition not unlike some 

 of those already encountered in the first two examined, namely, a large central 

 mass grouped about the central biotype 7, and isolated groups of biotypes 1, 10, 

 and 13 in both sexes. In the second generation in this season the distribution 

 of the population showed about the same condition of the central mass of the 



1488 Males. Total 3310. 1822 Females. 



FiO. 101. — Census of first annnal generation at Fuebla in 1904, showing condi- 

 tion of the pronotal pattern and presence of several strongly marked Isolated 

 groups. 



2390 Males. 



61 



Total 5010. 



2620 Females. 



Fig. 102. — Census of second annual generation at Fuebla In 1904, showing 

 essentially the same conditions as found in previous censuses. 



population and the same isolated groups, with the exception that in the males 

 the groups composed of biotypes 10 and 12 were wanting. The records of the 

 conditions in these two censuses are shown in figures 101 and 102. 



In the season of 1905 both censuses showed the complete absence of isolated 

 groups and a nearly complete distribution of the population over the entire area 

 that the pattern covers. The season was especially favorable, with regularly 



