The European tree frog ("Hyla arborea") is a small tree frog. Other models of cheating include the European tree frog, "Hyla arborea". Amphibians include the stripeless tree frog, "Hyla meridionalis". For example, the male gray tree frog, "Hyla versicolor", produces a call to attract females. Hyla is a genus of frogs in the tree frog family Hylidae. It was initially placed in the tree frog genus "Hyla". The "Hyla versicolor" male increases calling rate and duration once a female is in vicinity. "Corethrella" species have been observed sucking blood from individuals of the tree frog genus "Hyla". The most common amphibians recognized were frogs ("Rana" and "Hyla"). The most widely used is an image painted by Adolf Hyla. Eleven species previously placed in the genus "Hyla" were moved to this genus. Until recently, the California tree frog was classified in the genus "Hyla". Twenty-three species previously placed in the genus "Hyla" were moved to this genus. The 15 species in this genus were previously placed in the genus "Hyla". Only geographical, rather than morphological, differences separates "Dryophytes" from the genus "Hyla".