558 
Journal of Agricultural Research 
Vol. XI, No. ir 
in opposite parts of the continent and under widely different environ¬ 
mental conditions. It may well be that the dry, cool climate of the 
coast of California, where com is grown under irrigation, would bring 
into prominence a somewhat different complex of protective factors than 
the relatively hot, moist climate of Maryland. 
Table V gives the general average of the 14 progenies that were planted 
both seasons with respect to the different characters based on the upper 
ears and the interannual correlations for the different characters. It will 
be seen that the infestation was much more severe at Chula Vista, Cal., 
than at Lanham, Md. This is best indicated by the average number of 
larvae. The damage per larva and the total damage were both increased 
at Chula Vista by the fact that in 1915 many of the ears were allowed 
to mature before the notes were taken. The pronounced environmental 
differences between the two localities is indicated by the fact that the 
time from planting to silking was, on the average, 23 days longer at 
Chula Vista than at Lanham the following year. In view of the much 
slower growth of the plants at Chula Vista, it is reasonable to assume 
that the grains were also slower in maturing. This would expose the 
ears to the attacks of the larvae for a longer time and would tend to 
increase the damage per larva and total damage. 
Tabi ,3 V .—General mean of the different characters of 14 progenies in 1915 and 1916 and 
the interannual correlation 
Factor. 
Damage. 
Number of 
larvae. 
Damage per 
larva. 
Prolonga¬ 
tion. 
Dength of 
husks. 
Dength of 
ear. 
General mean, 1915. 
General mean, 1916. 
Interannual correlation. 
3- 22 
•65 
* 37 ±o. 16 
!• 75 
.84 
. 73±o.Q9 
Grades. 
1. 76 
•76 
• 38 ±o. 16 
Cm. 
9-32 
5-88 
• 79 ±0.07 
Cm. 
23.6 
26.6 
. 76 ±o. oS 
Cm. 
14-3 
20. 7 
.02±0. 19 
Factor. 
Number of 
husks. 
Number of 
layers. 
Days to 
silking. 
Husk Number of 
leaves. rows. 
General mean, 1915.... 
General mean, 1916.... 
Interannual correlation 
12-9 
12.7 
•53 ±0.13 
9.8 
9.9 
. 62 ± 0 . II 
105.2 
82.0 
• 5i±o. 13 
Grades. 
1-55 
3-24 
• 39±o. 16 
14.6 
15-3 
• 72 ± 0 . 0 <* 
Seventeen of the progenies grown in 1916 were descended from the 
fourteen progenies gjown in 1915. The behavior of these progenies 
affords some evidence regarding the intensity of the inheritance of the 
measured characters. To reduce the agreement between parent and 
offspring to a quantitative basis, the mean values of the seventeen 
progenies and the mean values of their parent progenies, both grown in 
1916, were correlated. Eight of the new progenies grown in 1916 were 
not descended from single 1915 progenies, but resulted from crosses be¬ 
tween different 1915 progenies. In these cases a midparental value was 
taken by averaging the mean values pf the two parents. The correla¬ 
tion coefficients are given in Table VI. 
All of the correlations are positive and all are apparently significant. 
The average of the coefficients for the n measured characters was 0.60. 
