NOS. 622-623] THE SEXES IN THE APHID 



509 



As a rule the parents for the following generation were 

 taken from the first of the host plants, and were trans- 

 ferred to a young healthy plant, on which they produced 

 their young. 



This particular experiment was started in June from a 

 stock whose stem mother hatched in the greenhouse in 

 the preceding January. The line had passed through a 

 sexual phase in that time, but had been preserved by a 

 small number of viviparous females. In Table I the line 

 from apterous parents is represented in the upper half 

 of the table, the line from alate parents in the lower half. 

 For the sake of comparison the totals are placed together 

 at the bottom of the table. 



There is a striking preponderance of winged offspring 

 in the families of wingless parents, and a preponderance 

 of wingless offspring from winged parents. 



