Crickets have very noticeable exterior sex differences, including the highly visible ovipositor, a reproductive organ seen in female crickets. Male and female crickets also display notable behavioral differences.
Look at the cricket's rear end. An adult cricket will have two visible cerci, with one protruding from each side of its abdomen. A cercus has a needle-like appearance, and it acts as a sensory organ in both males and females. On male crickets, the cerci are generally more prominent.
Check between the two cerci for an ovipositor, which is similar in appearance to a cercus but slightly longer. The ovipositor sits directly between the two cerci, as a tail-like appendage. A female cricket will have three abdominal protrusions, consisting of two cerci and an ovipositor, while a male will have two cerci only. A female cricket's ovipositor enables her to deposit eggs on the ground after fertilization.
Listen for chirping. Adult male crickets chirp using a process known as stridulation. They create this characteristic sound by rubbing serrated wing veins together. Females lack the ability to chirp, so a cricket who emits this sound is certainly a male.