The Doo-lally Tap

from Deolali, a British army camp 100 miles north-east of Bombay where British soldiers would stay after finishing their tour of duty, to await transport back to Britain; and tap, a Persian or Urdu word for a malarial fever (ultimately from Sanskrit tapa, meaning "heat" or "torment")

Noun phrase

doolally tap
camp fever
madness, eccentricity

Wikipedia

Doolally

Deolali Camp

World Wide Words