John W. Grula, Orley R. Taylor, Jr., Some Characteristics of Hybrids Derived from the Sulfur Butterflies, Colias eurytheme and C. philodice: Phenotypic Effects of the X-Chromosome, Evolution, Vol. 34, No. 4 (Jul., 1980), pp. 673-687
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Grula et al. (1980) studied this question.