They are carnivorous, preying on small insects such as psylla and flies. There are at least 110 described species in "Psylla". These 111 species belong to "Psylla", a genus of plant-parasitic hemipterans in the family Psyllidae. The adult "Psylla pyri" is between long. These psylla rest with their wings folded roof-like over their abdomens. This psylla overwinters as an adult, concealing itself in a crack in the bark.