132 
Variation and Inheritance in Aplm 
rapid growth has passed. Among immature females with a frontal breadth of 
12 — 13 units the length of the antenna tended to be about five-thirds of the 
frontal breadth ; among viature females, that had practically ceased to grow, with 
a frontal breadth of 16 — 17 units, the length of the antenna had risen to about 
seven-thirds of the frontal breadth. To insure that the individuals preserved were 
mature I generally left the families until one or more of the members began to die 
of old age. To emphasize the importance of this procedure it may be added that 
since the value of the ratio rises with the growth of the mother there could easily 
be introduced into the correlation between offspring and mothers a wholly spiuious 
correlation, which has no reference to heredity, by inserting into the series a group 
of immature mothers with offspring at the same immature stage. 
(3) Injimitce of Environment. 
During the period when the mothers were selected the environment was very 
favourable, the temperature was high and the foliage of the plants was in good 
condition. Later, while the offspring Avere growing and especially when the grand- 
children were developing the conditions were much less favourable. Much rain 
and a considerable fall of temperature occurred, also the foliage of the columbines 
was withering, as is always the case in late summer. 
The unfavourable conditions of the environment progressively increasing had a 
marked effect on the absolute size attained by the 'mature individuals ; this is well 
seen by comparing the third and fifth columns with the second in the accompany- 
ing table. In the second generation the absolute length of the antenna was not 
diminished in the same proportion as the breadth, and hence the mean of the 
ratios (23'4G9) was higher than in the parents. In the third generation we see the 
great effect of the environment, the means of the absolute dimensions of the 
mature individuals being very conspicuously lower than in the first and second 
generations. 
TABLE I. 
Means. 
Dimension 
Mothers (60) 
weighted with 
their fertility 
Children 
(368) 
Grandmothers 
(30) 
weighted with 
their fertility 
Grandchildren 
(291) 
Frontal Breadth {AB) 
Unit ='01 ram. 
37-646 
35-898 
37-562 
33-932 
Length of R. Antenna [CD) 
Unit = "01 mm. 
85-263 
84-336 
83-907 
76-586 
Ratio 10 
A /} 
22-670 
23-469 
22-464 
22-567 
