Crickets are small to medium-sized insects with mostly cylindrical, somewhat vertically flattened bodies. The head is spherical with long slender antennae from cone-shaped scapes (first segments) and just behind these are two large compound eyes. On the forehead are three ocelli (simple eyes). The pronotum (first thoracic segment) is trapezoidal in shape, robust, and well-sclerotized. It is smooth and has neither dorsal nor lateral keels (ridges).
At the tip of the abdomen is a pair of long cerci (paired appendages on the rearmost segment), and in females, the ovipositor is cylindrical, long and narrow, smooth and shiny. The femora (third segments) of the back pair of legs are greatly enlarged for jumping. The tibiae (fourth segments) of the hind legs are armed with several moveable spurs, the arrangement of which is characteristic of each species. The tibiae of the front legs bear one or more tympani, which are used for sound reception.
The wings lie flat on the body and vary in size between species, being reduced in size in some crickets and missing in others. The fore wings are elytra made of tough chitin, acting as a protective shield for the soft parts of the body and, in males, bear the stridulatory organs to produce sound. The hind pair is membranous, folding fan-wise under the fore wings. In many species, the wings are not adapted for flight.
The family’s largest members are the 5 cm-long bull crickets (Brachytrupes), which excavate burrows a metre or deeper. The tree crickets (Oecanthinae) are delicate white or pale green insects with transparent fore wings, while the field crickets (Gryllidae) are robust brown or black insects.