ABSTRACT. – We studied the effects of two ecdysteroid analogs (RH-0345 and RH-2485) on the growth and on the hemolymph and ovarian protein concentrations of the centipede Eupolybothrus nudicornis used as a model of predators of soil fauna. Sublethal doses of RH-0345 and RH-2485 significantly reduce total body and ovarian weights compared with those of controls. The decrease in ovarian weight is proportional to the decrease in total body weight because the gonadal somatic index remains constant and is the same among controls and intoxicated animals. RH-0345 and RH-2485 also reduce significantly the total protein concentrations in both the hemolymph fluid and ovarian tissue of females. Taken together, the observed decrease in total body and ovarian weight and total protein production is indicative of a decrease in total growth.