The author made the investigation about the olfactory response of newly hatched silk-worm against leaves of mulberry chrysanthemum, Fatisia japonica, fig, horse bean, and blue onion, and certain number of synthetic chemicals. The results were as follows.
1. The crawing speed against mulberry leave was different among each strains.
2. The olfactory response or chemotropism against leaves of mulberry was more distinct than that against the other leaves in the case of inbred strains, but in the case of certain mixed bred strains, some strains were more sensible against the leaves of latter plants than thet of mulberry.
From above mentioned facts, it might be concluded that the genetic factors have influence on the sensitivity of silk-worm.
3. About chemotropisim against synthetic chemicals, only one strain out of four showed response against certain aldehydes.