The present studies were carried out, under natural room condition from June to July in 1969. The period required for growth of eggs and larva varied according to various temperatures and methods of rearing. The average number of eggs laid by the Culex pipiens pallens was 137 per egg raft. The period of gonotrophic cycle was from 3 to 6 days: incubation period of eggs was from 1.5 to 2 days: larva period was from 10 to 14 days: pupa period was from 2 to 3 days. Accordingly, the period from the beginning of gonotrophic cycle to the adult mosquitos in next generation required 25 days at the longest and 16.5 days at the shortest.
