The best membrane and the optimum temperature for experimental feeding of ARGAS (Persicargas) Arboreus Kaiser, Hoogstraal, and Kohls proved to be Baudruche skin (commercially prepared from bovine intestine) at 38°C, a temperature within the normal range of the natural bird host of this tick species. Different blood components from herons, chickens, pigeons, and rabbits were offered to 2nd instar nymphs and to adults. Whole blood from birds was more efficient for the ticks' molting and oviposition than bird plasma or rabbits' whole blood, cells, or plasma. Contrary to usual findings in studies of bloodsucking insects, stretching of Arboreus nymphal integument during engorgement appears in itself not to release molting hormone. In this tick, the presence of a suitable nutrient, combined with the stretching effect of engorgement, apparently are important factors for successful molting.