]20 SURVEY OF INVERTEBRATES 



time, encounter situations in which llieir oxygen con- 

 sumption will be greatly reduced. 



After a heavy rainfall many terrestrial insects may 

 be immersed temporarily in water. They then close their 

 spiracles and must get along wdtli the little oxygen they 

 can obtain by cutaneous respiration. This change will 

 frequently imply that at least part of the metabolism 

 will have to become anaerobic. Similar conditions ought 

 to be especially frequent along beaches. 



That the larvae of hees within the cells of the hive 

 may live under sharply reduced oxygen tensions seems 

 probable but has not yet been investigated. The fact 

 that the respiratory quotient of larval queens and work- 

 ers is higher than 1, even when investigated at the oxygen 

 tension of the atmospheric air (Melampy and Willis, 

 1939) is perhaps significant in that connection. On the 

 other hand, it is certain that the air enclosed in the cocoons 

 of silk worms has, nearly always, a high oxygen con- 

 tent (Regnard, 1888; Portier and Rorthays, 1926). 



But even a sufficient oxygen supply does not necessar- 

 ily indicate that all processes must be aerobic at all 

 times. Kozancikov (1935) has shown that the larval dia- 

 pause of some Pyralidae "is characterized by anoxybi- 

 otic rearrangements." The nature of these processes 

 will be discussed later. 



B. Experimentally induced anaerohiosis. Some early 

 investigators (Vauquelin, 1792; Emery, 1869; Bert, 

 1878) confined insects in closed vessels and found that 

 they became immotile after a certain length of time. 

 Analyses of the remaining air, performed in some cases, 

 showed that the oxygen had more or less completely dis- 

 appeared; upon readmission of air the animals usually 

 revived. 



Many other investigators simply immersed insects in 

 ordinary water, assuming that this would cut them off 

 from their source of oxygen. This method which was 



