Study on biology of Z. bicolorata carried out on P. hysterophorus plant at Department of Zoology. The Z. bicolorata reared on the Parthenium potted plant and insect rearing cages. The study show that the Mexican beetle oviposit small, oblong, elongated, light yellow or orange eggs mostly on upper and lower surface on leaf occasionally on flowers rarely on stems. The mean value of fecundity 581.25±61.16, incubation period in days 4.6±0.68, hatching percent (%) 69.55±4.33, larval period 1st, 2nd, 3rd and 4th instar respectively 4.25±0.72, 3.40±0.50, 3.95±0.83, 4.85±0.88, pupal period 1.4±0.50, Pupal period, Pre-oviposition period 9.25±0.72, Oviposition period 35.45±4.30, Post-oviposition period 16.90±2.36, Total life cycle days were recorded 32.50±5.39, adult longevity male 32.85±8.56, and female was 40.75±6.50 and total survival of days of adult beetle were 73.60±9.06.