Cat flea larvae feeding on the feces of adult fleas that were maintained on cats and were provided with frozen flea eggs ad libitum each consumed an average of 21.7 +/- 3.9 eggs and developed rapidly with 100% adult emergence. In contrast, 93.4% of larvae held individually and provided with only flea feces did not survive to the adult stage. Developing larvae consumed eggs in the presence of yeast and rearing diet. In a second experiment, larvae provided with flea feces and eggs and maintained at 55% RH consumed 26.9 +/- 2.7 eggs per larva, compared to larvae maintained at 75% RH that consumed 20.4 +/- 1.9 eggs per larva.