black-headed, crowned, + flat-headed snakes

 

Mexican Black-Headed Snake (Tantilla atriceps)

Southeastern Crowned Snake (Tantilla coronata)

Trans-Pecos Black-Headed Snake (Tantilla cucullata)

Flat-Headed Snake (Tantilla gracilis)

Smith's Black-Headed Snake (Tantilla hobartsmithi)

Plains Black-Headed Snake (Tantilla nigriceps)

Rim Rock Crowned Snake (Tantilla oolitica)

Western Black-Headed Snake (Tantilla planiceps)

Florida Crowned Snake (Tantilla relicta)

Chihuahuan Black-Headed Snake (Tantilla wilcoxi)

Yaqui Black-Headed Snake (Tantilla yaquia)