none no species A little-known leaf-mining sawfly, Profenusa alumna , was responsible for severe browning and defoliation of northern red oak, Quercus rubra L., from 1956 to 1968 in Maine. All life stages were observed under both field and laboratory conditions to investigate its developmental and population biology. This sawfly overwintered as a prepupa in the soil. No males were found among thousands of adults examined. Populations subsided in 1968, following a sharp increase in larval and egg parasites. Parasitism of mature P. alumna larvae by Endasys sp. alone reached 75% in heavily infested areas in 1968. Life cycle and development; Life cycle; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Host parasite relationships; Ecology; Population dynamics; Population structure; Land and freshwater zones; Nearctic region; North America; USA Profenusa alumna (Tenthredinidae); Life cycle; Developmental stages; Characteristics; Hymenopteran parasites; Plant hosts; Quercus rubra (oak); Life history characteristics; Prevalence; Endasys; Population dynamics; Mortality; Factors; Population sex ratio; Maine; Distribution & life history Endasys (Ichneumonidae); Hymenopteran hosts; Prevalence; Profenusa alumna; Maine