- 152 — 
well illustrated by some of Toyama’s experiments on Silk-worms. 
In certain cases, as in Abraxas gr ossidar iata and its lacticolor 
variety, reciprocal crosses give a different result, and this has led 
to an interpretation of sex-differentiation in Mendelian terms. It 
was suggested that this case may provide the clue to those curious 
cases of polymorphism among Butterflies where only the females 
are affected. In conclusion it was pointed out that if breeders of 
Lepidoptera would familiarise themselves with the Mendelian 
principles of heredity, and direct their experiments in accordance 
with them, results of great scientific value might be looked for. 
Après avoir remercié le conférencier, le Président annonce qu’il 
clôt la séance générale et engage les congressistes à se rendre à la 
séance de la Section d’Évolution et de Mimicry, la seule qui se 
tiendra ce matin. Par contre, il espère que beaucoup d’adhérents 
accompagneront les membres dévoués qui s’offrent à les piloter à 
Tervueren et à Waterloo. 
