Cannibalism is a well-known behavioural phenomenon that is supposed to be an adaptive response to ecological resources. The total number of eggs, incubation period, developmental period, and adult longevity of Scymnus interruptus was studied in three experiments, in which S. interruptus, the hibiscus mealybug Maconellicoccus hirsutus (Green), and S. interruptus+ M. hirsutus were singly used as prey in the laboratory. The mean life cycles of the females fed on S. interruptus, or M. hirsutus, or S. interruptus+M. hirsutus were 41.11, 34.25, and 46.18 days, respectively. The findings showed that S. interruptus preferred S. interruptus+M. hirsutus compared to the other prey types, as it developed speedy  (17.12days)   The Oviposition period of female was 21 days with an average of laid eggs as 218.32 egg/female. Fourth instar grub ate significantly more mealybugs than 1^st, 2^nd and 3^rd instars. The highest consumption rate of S. interruptus during its total life period was recorded as (1119-1362) mealybugs individuals, whose parents were fed on S. interruptus + M. hirsutus.