KEY TO MEXICAN LEPTODACTYLID GENERA

1. Small (20-40 mm.), pustular, toadlike frogs; maxillary and premaxillary bones not bearing teethEngystomops

Large (20-110 mm.), smooth skinned and non-toadlike frogs; maxillary and premaxillary bones bearing teeth2

2. No conspicuous waist (Fig. 5); sternum bearing bony style,Leptodactylus

Constrictions at waist (Fig. 5); sternum cartilaginous, no bony style3

3. Few (less than six), if any, supernumerary tubercles on plantar surfaceEleutherodactylus

Many (more than 8) supernumerary tubercles on plantar surfaces4

4. Terminal, transverse groove across tip of digits, especially outer two fingers, digits expanded or not; small frogs (18 to 40 mm.)5

Tips of digits lacking transverse groove; digits unexpanded; medium-sized to large frogs (37 to 94 mm.)Hylactophryne

5. Lumbo-inguinal gland compact, ovalTomodactylus

Lumbo-inguinal or inguinal gland absent or diffuse and irregular in outlineSyrrhophus