Crickets come in many varieties, from the familiar field cricket to tree and cave crickets. They go through incomplete or gradual metamorphosis, meaning the young insects resemble adults but don't have wings or reproductive organs. Crickets molt as they grow, shedding their skins anywhere from six to 18 times before reaching adulthood. Every adult female cricket has a conspicuous egg-laying tool called an ovipositor at the end of her abdomen; this enables you to tell males from females.
Look for a mature cricket and examine the end of its abdomen. Locate the paired slender appendages protruding backward from the sides of the abdomen; these are called the cerci and function like a pair of backward antennae.
Look between the cerci to see if an unpaired slender ovipositor projects backward from the end of the abdomen, resembling a spear or needle. (In camel crickets it is often half the length of the body.) Your cricket is female if the ovipositor is present and male if not.
Examine a large immature cricket to see if the ovipositor has begun to form at the end of the abdomen, since ovipositors can begin to show before the cricket is an adult. Your young insect is female if you can see an ovipositor, even if it is short.
Examine the wings of mature crickets as another means of separating males from females. Look at the base of the forewings for the thickened song-making structures called the file and scraper. Identify the insect as a male if these are present, since females can't sing. Look at the width of the wings in tree crickets: females have narrow wings and males have broad, paddle-shaped wings.