Biological attributes relevant to the reproduction, survival and development of Snellenius manilae, a larval parasitoid of the common cutworm (Spodoptera litura), were studied. The mode of reproduction of the laboratory population of S. manilae was arrhenotoky. The pattern of egg maturation and deposition in S. manilae did not fit the strict dichotomy (synovigenic versus pro-ovigenic) but followed the Type 2 index wherein initial egg loads are lower and egg deposition increases on the first few days of life before declining rapidly. The highest number of mature ovarian eggs was recorded on day 3 and then gradually decreased on each successive day until the wasp died on day 6. The ovipositing female did not discriminate already parasitized larvae. Duration of ovipositor insertion was very short (1 – 2 s) and was made by the female across the cutworm body with the highest number made within the head region. S. manilae is a koinobiont parasitoid and oviposits across the first three larval instars but progeny production and parasitism were highest in the first instar cutworm larva for both no-choice and choice method. S. manilae underwent three larval instars. The total developmental period of the parasitoid from egg deposition to pupation was 10.5 ± 0.08 d, pupation to adult emergence was 4.2 ± 0.10 d, while the adult lived for 6.1 ± 0.07 d with honey as food.