In the course of genetical investigations (Harrison, 1920) in the lepidopterous genus
Oporabia
I conceived the idea that the inherited instinct of
Oporabia
filigrammaria
HS. to deposit its eggs on heather (
Calluna vulgaris
) was the direct result of long-continued isolation on treeless heather-clad moorlands, involving a compulsory diet of that plant; in other words, I felt that the development of the instinct and its inheritance were Lamarckian effects. To test these views experimentally, by attempting a transference in the food habits of other insects, seemed far from difficult, and search was forthwith made for material easy to manipulate in captivity. No forms appeared more adapted for the purpose than the Geometrid moths
Lycia hirtaria
Cl. and
Phigalia pedaria
F., which I had employed in former experiments. However, the technique adopted, at any rate as applied to these insects, proved unsatisfactory and had therefore to be modified. Unexpected difficulties, riot in securing oviposition in a state of semicaptivity but in its taking place in a natural manner on the food plant, were immediately encountered.
Inheritance of Acquired Characters
