During the spring 2004, some specimens of a tachinid fly were collected from pupal cocoons of weedy spurge leaf defoliator moth, Simyra dentinosa F. (Lep.: Noctuidae). The specimens were identified by the last author as Nilea anatolica Mesnil, 1954 (Dip.: Tachinidae). The body length and alar expanse in males vary from 7.0-7.5 mm and 14.5-15.5 mm, respectively. In females, body length and alar expanse vary from 9.0-9.2 mm and 16.5- 17.5 mm, respectively. Apex of hind tibia with posterodorsal preapical seta and scutellum is light brown in color. This fly parasitizes the final larval stage of the defoliator moth and its larval development is synchronous with the initiate of prepupal stage of the moth. After complement of the larval stage, larvae leave the host and pupate inside the cocoon of moth and overwinter as pupa inside the host cocoon.