The biology ofTyphlodromalus peregrinus(Muma) was studied in the laboratory at 26°C. Each of the following organisms was evaluated as suitable diet: all stages ofTetranychus urticaeKoch; immature stages ofPanonychus citri(McGregor) (Acari: Tetranychidae); and pollens ofMalephora crocea(Jaquin),Quercus virginianaMiller, andTyphalatifolia(L.). The combination ofT. urticaewith each pollen was also tested. Total developmental time ranged between 5.73 and 7 d for females and between 5.67 and 6.93 d for males. The percentage of females in the total population ranged between 53 and 61%. A diet ofT. urticaeprovided the shortest generation time (G), greatest female longevity, and mean total fecundity (F) which resulted in the highest net reproductive rate (R0) value (25.31 expected females per female), intrinsic rate of increase (rm= 0.224), and finite rate of increase (erm= 1.25) per day forT. peregrinl1s. Diets of onlyP. citriorM. crocearesulted in close values of G = 8.67, 8.91; F = 47.11, 49.47; R0= 24.00, 26.65; rill = 0.210, 0.219; anderm= 1.23, 1.24, respectively.Q. virginianaandTypha latifoliawere the least favorable food sources, with results of G = 8.78, 9.41; F = 30.38, 24.25; R0= 14.20, 12.04;rm= 0.193, 0.170, ander= 1.21, 1.18, respectively. Thermvalues were highly affected by generation time and mean total fecundity (R2= 0.947).