We scrutinized variability in colour polymorphism and sex ratio of the cone-headed tettigoniid Ruspolia differens (Orthoptra: Conocephalidae) in north-west Tanzania during periods of swarms and of non-swarming phase. Six key colour morphs were characterized together with their continuous and discontinuous sub-morphs. Seasonal weather alterations evidenced to alter the relative frequency and sex-ratio biasness of these morphs. During dry season the equilibrium of colour polymorphism favours the frequency of the browns and the population is chiefly male-biased, but during wet season the greens are favoured and the population is female-biased. This implies that these traits are directly governed by weather conditions and are subjects to vary with geographical regions. Tegmina coloration showed to be a sex-linked trait as brownness was associated with maleness whereas greenness was associated with femaleness. Further, tegmen speckles are a useful biomarker of inheritance of the browns and the greens are dominant over the browns. It was apparent that the distinct variability in colour polymorphism and sex ratio of this insect is its interactive strategy for inhabiting different weather and environments.