Eumastacidae

Definition

A family of grasshoppers (Orthoptera) commonly called monkey grasshoppers or matchstick grasshoppers, distinguished by slender legs held perpendicular to the body, often near horizontal; short antennae with a terminal sensory organ; three-segmented tarsi; absence of prosternal spine and tympanum; and frequently wingless condition. Members are considered morphologically primitive within Orthoptera and feed primarily on ancestral plant groups including algae, ferns, and gymnosperms. The family shows highest diversity in the Neotropics.

Etymology

Example

The neotropical genus Paramastax exhibits the family's characteristic horizontal leg posture and reduced wings, with nymphs and adults feeding on understory ferns in cloud forest habitats.

Synonyms

• Monkey grasshoppers
• matchstick grasshoppers

Related Terms

• Orthoptera
• Caelifera
• Acrididae
• prosternal spine
• Tympanum
• neotropics
• aptery

Usage Notes

The family is sometimes treated as the sole member of superfamily Eumastacoidea. The common name 'monkey grasshopper' refers to the simian-like posture of the forelegs, not phylogenetic affinity. Species-level identification often requires examination of male genitalia and tarsal segmentation. The absence of a tympanum renders these grasshoppers deaf to the airborne sounds produced by many other orthopterans.