“An interesting, though rather detestable, creature called the ant-lion is found in some of the bestiaries of the Middle Ages… The ant-lion was so called because of its size, since ‘while to other animals it is only an ant, to ants themselves it is as if it were a lion’.
“As an instance of the implicit credulity of the Middle Ages witness this account of the ant-lion given in the Physiologus. This states that the ant-lion’s father was shaped like a lion and his mother like an ant. The father was a flesh-eater; its mother herbivorous. When these two had issue, this was the ant-lion, partaking of the features of its parents, its forepart being that of a lion and its hindquarters like an ant. Being thus composed the wretched insect could neither eat flesh like its father nor herbs like its mother, and so it starved to death!”
Colin Clair, Unnatural History : An Illustrated Bestiary (1967). Alas, the ant-lion is not illustrated in the book, and nor is the gigantic gold-digging pismire, with which it shares a chapter.