428 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1912. 



hairs. If the first generation is fed with wahiut leaves, the second 

 with oak leaves, and the third with Esparsette, then the characters 

 of all three food-response forms are united in the last generation. 



Schroder likewise obtained in the small willow-leaf beetle Phratora 

 vitellinae (fig. 7, lower right) an inheritable food change, but wliich at 

 the same time forced the animals affected to a change in locomotion 

 combined with a change in reproduction. The larvae of tliis beetle, 

 usually fed upon the leaves of a smooth species of willow (fig. 7A), 

 were unable to feed upon the surface and were forced to mine in the 

 tissue of the leaf. When both willows were at the disposal of the 

 resulting beetles (B, h; C, c, etc.), then these fastened their eggs, 

 increasingly with each generation from the very beguining, freely to 

 the new food plant. 



Another experiment by Schroder affected the nidification of a 

 small moth {Gracilaria stigmatella) . The caterpillars of this moth 

 are accustomed to roll in the tips of the willow leaves, which serve it 

 as an abode and food. They are prevented from doing this when the 

 tips of the leaves are cut off and are thus forced to roll up one or both 

 edges of the leaf. The progeny of the third generation do this in part 

 spontaneously, even when the leaves have not been mutilated. 



Plants, too, yield positive results when they are examined for 

 transmission of acquired characters. I will have to pass over the 

 many examples which have been noted in the asexually reproduced 

 spore plants, bacteria, yeasts, smutsj and algae. I can only mention 

 those produced sexually, usually by self-fertilization of the bisexual 

 flowers. 



Klebs grew Gamander-Ehrenpreis ( Veronica chamaedrys) , a species 

 of quite constant form under especially favorable food conditions, in 

 moist, well fertilized beds. If the feeding sap stream was driven into 

 the flowering stalk by the cutting away of the main stem and any 

 new lateral shoots which might develop, then these changed quite 

 rapidly into leaf shoots. No new flowers with their accompanying 

 bract were added, but in their place only broad coarsely serrate green 

 leaves. The disposition to this leafy eflSorescence is increased in the 

 seedlings of such changed plants, even without mutilation in the free 

 bed, and, under food conditions which were little more favorable than 

 those in which the wdld plants grew, several seedlings showed a change 

 of theh unbranched determinate flower stalks into branched indeter- 

 minate leaf shoots. 



Recent experiments w^ere made by Klebs upon the short-leafed 

 live-for-ever (Sempervivum acuminatum). This was carefully grown 

 and the development of the flower stalk watched; then the flowers 

 were examined, and, if found normal, the whole flower stalk was cut 

 off. New flower stalks now developed of a different form, with 

 changes in the number- and position of the flowers, pistils, and sta- 



