122 SURVEY OF INVERTEBRATES 



Luciani and Piutti, 1888; Reg-en, 1906; Walling, 1906; 

 Schwartz, 1908; Cook, 1932; Gilmour, 1940; Harnisch, 

 1939, 1941) or removed the oxygen by evacuation or ab- 

 sorption (Kalmus, 1935; von Brand, 1943). 



The more important results have been summarized in 

 Table 16. It will be seen from this table that the anaero- 

 bic periods tolerated by terrestrial insects are rather 

 short. If we disregard the exceptional survival periods 

 reported for ants in submersion experiments (Devaux, 

 1891; Fielde, 1904, 1904a), survivals which, as sho\\Ti 

 above, may be due to faulty technique, it becomes appa- 

 rent that the insects are not well equipped for anaerobic 

 life. 



This becomes all the more evident if one studies the 

 behavior of insects in the complete absence of oxygen. 

 Practically all investigators agree that the animals then 

 become motionless in a very short time, a fact w^hich in- 

 dicates definitely that they are unable to maintain normal 

 life processes. The paralysis thus established seems to 

 be preceded in some instances by a brief period of exci- 

 tation. This has been described for various coleoptera 

 by Babak and Foustka (1907), for Carabus by Schwartz 

 (1908) and for grasshoppers by Lee (1925). 



Since, in most cases, the paralysis comes about very 

 rapidly, it is questionable whether its onset is actually 

 due to an accumulation of non-oxidized metabolic end- 

 products. It seems more likely that an acute oxygen 

 shortage, affecting first the more sensitive nerve centers 

 is responsible for the phenomenon. There is, however, 

 no doubt that when anaerobic conditions are maintained 

 for a long time an accumulation of such endproducts 

 does occur and that it is then linked with the persis- 

 tence of the paralysis. This is clearly evidenced by the 

 two following facts. First, it has been generally recog- 

 nized that the time required for full recovery, as judged 

 by the resumption of normal motility, is directly de- 



