“…The diverse functions of the air sacs in the insect have been summarized by Wigglesworth (1963Wigglesworth ( , 1972. Further, they are thought to act as bellows in ventilating the tracheal system (Bets, 1933), to guarantee an intensive ventilation of the trachea during breathing (Demoll, 19271, to act as sound resonators (Pringle, 1957;Church, 19601, to act as heat insulators (Weis-Fogh, 1964a1, to assist in egg laying and molting (Clarke, 19571, and to permit the build-up of sufficient pressure to supply air to smaller tracheae (McCutcheon, 1940). In Hymenoptera, there is a good correlation between the development of the air sacs and the size and activity of the various species of insect (Tonapi, 1958).…”