A complete rearing medium for Drosophila and similar organisms. No cooking or sterilizing--just add water. A new culture can be set up in less than a minute. Each liter of Formula 4-24(r) will prepare 75 to 85 Drosophila Culture Vials (173120). Yeast, measuring cups, and instructions are included in each order. A blue coloring agent is added to facilitate observation of the larvae. Contains four 4 L bags of media.