136 SUMMARY 



oxygen, while other chironomids are not able to do so, is 

 still unanswered. 



5. Adult aquatic insects are not very resistant to the 

 lack of oxygen. 



6. Terrestrial insects are only rarely exposed to severe 

 oxygen deficiencies in nature; their resistance to experi- 

 mental anaerobic conditions is not well developed either. 



7. A low oxygen tension influences certain functions 

 such as the rate of mutations in some insects; in Droso- 

 phila, for example, the rate of mutations is increased 

 following periods of asphyxiation during the pupal 

 stage. 



8. Limulns seems to survive relatively long periods 

 without oxygen; anaerobic metabolism may play an im- 

 portant role in the survival of this animal in nature. 



9. The resistance of tardigrades to oxygen deficiencies 

 depends on their water content ; desiccated specimens are, 

 of course, extremely resistant. 



10. Gasterophilus larvae are better adapted to anaerobic 

 life than the other parasitic arthropods so far studied, 

 but even they do not survive for indefinite periods with- 

 out oxygen. 



11. The cases of urinary and intestinal myiasis offer 

 interesting, though still unsolved problems on the mode 

 of survival of various insects and larvae under low oxy- 

 gen tensions. 



