On a Theorem of Weyl Concerning Eigenvalues of Linear Transformations I

11 No attempt was made to detect autosomal recessives. 12 The F2 progenies derived from X YY males and C1B females were examined micro- scopically in order to eliminate the possibility that patroclinous sons resulting from secondary non-disjunction might mask a lethal.13 Breeding tests were conducted on all flies showing conspicuous, symmetrical altera- tions in phenotype, and such changes were scored as mutants even in those cases where inviability or sterility prevented actual progeny counts.14 It should be noted that it was not possible to compare the recessive lethal rates in the two kinds of sperm (X and X Y) from X YY males, as was possible in the case of visibles.