Common black cricket

Field crickets are normally 15–25 millimetres (0.6–1.0 in) in size, depending on the species, and can be black, red or brown in color. While both males and females have very similar basic body plans, each has its own distinguishing feature(s).
Females can be identified by the presence of an ovipositor, a spike-like appendage, about 0.75 inches (19 mm) long, on the hind end of the abdomen between two cerci. This ovipositor allows the female to bury her fertilized eggs into the ground for protection and development. In some female field crickets, species can be distinguished by comparing the length of the ovipositor to the length of the body (i.e. G. rubens has a longer ovipositor than G.texensis).
Males are distinguished from females by the absence of an ovipositor. At the end of the abdomen there are simply two cerci. Unlike females, however, males are able to produce sounds or chirps. Thus, males can be identified through sound while females cannot.
Diagram A shows the male cricket with its wings raised for the purpose of chirping. Diagram B shows the female cricket, identified via the long protruding ovipositor at the end of the abdomen. D and E show the female using the ovipositor to deposit the fertilized eggs into the ground. Diagram C shows a topical and side view of nymphs with no protrusion at the hind of the abdomen.