Wollastoniella rotunda Yasunaga et Miyamoto is an effective predator of Thrips palmi Karny and a potential biological control agent for this pest of Japanese greenhouse vegetables. To determine alternative sources of prey for the mass rearing of W. rotunda used for T. palmi augmentative biocontrol, we examined the life history parameters of this predator as reared on two different prey species: Tyrophagus putrescentiae (Schrank) and Ephestia kuehniella Zeller eggs. When the predator nymphs were reared on T. putrescentiae and E. kuehniella at 25°C, their developmental times were 21.0 and 16.7 days, respectively, and their survival rates on T. putrescentiae and E. kuehniella at 25°C were 43% and 91%, respectively. The longevity of the predator females was 13.1 days on T. putrescentiae and 19.2 days on E. kuehniella, and their total fecundity was 15.0 eggs on T. putrescentiae and 56.5 eggs on E. kuehniella. The intrinsic rate of natural increase per day of W. rotunda on E. kuehniella (r_m = 0.087) was greater than that on T. putrescentiae (r_m = 0.031). We thus concluded that E. kuehniella is more suitable than T. putrescentiae as food for the mass rearing of W. rotunda.