Abstract
Respiratory movements were recorded with strain gauge in 56 male adult cockroaches, Periplaneta australasiae FABRICIUS. Insects were studied for 200 days after imaginal ecdysis, within the period, each animal was recorded for 6 hours in a day. Younger adults showed slow but periodic abdominal respiratory movement with ventilation periods and pause periods. Typical periodic respiration persisted for at least 3 days after emergence. Thereafter, it gradually changed to aperiodic respiration. A few animals of 100 days or more after emergence entirely lacked ordinary abdominal respiratory movements.
