The populations of Anopheles fluviatilis James (1902), a foothill vector, collected from village Tilpuri of district Udham Singh Nagar and from villages Auspur, Ismailpur, and Durgapur of district Hardwar were maintained at National Institute of Malaria Research Insectory at 28 ± 1°C and 80–85% RH. Anopheles fluviatilis sensu lato was identified for two sibling species T and U. A total of 94% of the females of both species T and U oviposited by day 4 after the blood meal. Maximum hatching, that is, 80 and 62% of the eggs of species T and U, was observed on the second and third day, respectively. For species T, mortality in second and third instars was recorded to be 144 ± 9 (N = 1,600) and 48 ± 6 (N = 1,200), whereas in species U, it was 196 ± 13 (N = 1,400) and 70 ± 8 (N = 1,000), respectively. Mortalities in second instars of species T and U were significantly higher than third instars (P = 0.05). The female and male ratio in pupal stage of species T and U was found to be 53:47 and 58:42, respectively.