I watched blow fly (Diptera: Calliphoridae) larvae in western Maine that had consumed six animal carcasses so that I could identify patterns relating to when, how, and why they left the carcasses. The blow fly larvae stayed under the carcasses on hot, dry days, and then left them on rainy nights, traveling in random directions. Following several rainless days, the larvae left the carcasses at dawn on days with heavy dew and proceeded in a single 1-2-cm-wide column directly toward the rising sun. Species composition of one larvae column was nearly all or exclusively Phormia regina.