Abstract
Seven strains of Trichogramma, coming from different localities, were reared on eggs of Ephestia cartella, and their genetical behaviours were studied. The followings are the summary of our experiments.
1. Of the seven strains used, three were dark brown, two brown and two were pale yellow. Virgin females of all these strains produced males parthenogenetically.
2. The chromosomes are 10 in female and 5 in male, without any distinction either in number or in shape according to strains. One diploid male were observed in the IS (yellow) strain.
3. Cross breeding between the same colour strains was possible in any combination.
4. No cross between different colour strains was possible, except the one between IS (yellow) _??_ and BK (brown) _??_, where a small number of yellowish, sterile daughters appeared.
5. A male with vestigial antennae was found in the IS strain, but was sterile.
6. A vermilion-coloured eye mutant appeared in the BK strain. This character was completely recessive to the wild-type eye colour. In its fertility and vitality, however, the mutant was practically the same as the wild type.
7. Occasionally individuals with fused marginal cilia of hind wing appeared, but in no case was such abnormality inherited.
8. Inbreeding, X-ray-, colchicines-, or centrifugal treatment has no effect in inducing new mutation so far as our experiments go.
