274 Annals Entomological Society of America [Vol. IX, 



It must seem very peculiar, indeed, that, while we are unable 

 in general to recognize an ability to sleep among cold blooded 

 vertebrates, the nearest relatives of the sleep-demanding 

 mammals and birds, we should have for so large a number of the 

 much lower articulates such convincing evidence of a sleep 

 similar to that qf the highest organized animals. As far as my 

 investigations have gone this seems to be the case, the sleep of 

 insects appearing to be real sleep, while those sleep-like condi- 

 tions which are found among cold-blooded vertebrates, can 

 hardly be admitted into the catagory of actual sleep manifes- 

 tations. Startling as these conditions may seem at first glance, 

 upon reflection some of their surprising effects become clearer 

 when we recall how totally different is the distribution of the 

 physical and the psychological qualities in these widely sepa- 

 rated groups. 



In conclusion I wish to call particularly to mind that 

 among warm blooded animals those seem to have the most 

 pronounced form of sleep which have the intensest manifes- 

 tations of hfe (particularly again the birds). With such inten- 

 sive living the busy workers certainly deserve a few hours of 

 rest; we can surely appreciate their intensive desire for rest, 

 and that insects also ''get tired and sleep. " 



Sleep is a reflex of life, indeed, of the active manifestations of 

 life, the reflected image of the physical and psychological 

 activity of an organism. From this point of view we shall be 

 able to understand more clearly certain forms of sleep. In the 

 same way we shall be helped in explaining also the sleep of 

 insects, the richest group in genera in the animal kingdom, 

 which we meet at every step and whose existence, whose lives 

 are still so little known to us. 



