What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
Any of several kinds of caterpillar (especially those of the porina moth of New Zealand and moths of the Asian genus Thitarodes) when invaded and deformed by a fungus of the ascomycete genus Cordyceps while pupating underground.
Mid 19th century; earliest use found in The Sydney Morning Herald.