As the common name of this family says, Tetrigids are small grasshoppers, measuring at most 18 mm. There are, however, structural traits that help separate the Pygmy Grasshoppers from related families such as the Short-Horned Grasshoppers (Acrididae).
In family Tetrigidae, the pronotum extends far back over the abdomen, and is sometimes as long as or longer than the abdomen. The forewings (tegmina) are very short.
Because members of this family overwinter in the adult stage, they are among the first adult grasshoppers to be seen each spring.
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American Insects site