Abstract
Outbreaks of the primary screwworm (Cochliomyia americana C. and P.) in previously uninfested districts in recent years (Dove and Parman (1935), Dove and Bishopp (1936), King and Bradley (1935), Knipling and Tate (1935), Laake (1935), Robinson (1935)) have created a greater need for a means of recognizing the larvae of C. americana and other wound-invading blowflies.