1916] The Sleep of Insects 235 



In August of the following year at Lake View, Kansas, 

 sufficient observations were made on the sleeping habits of these 

 insects to prove that in this instance the males had not congre- 

 gated for the purpose of meeting the females, but that the males 

 alone of this species are gregarious in habit, and perhaps all in 

 the region 'round about occupy one centrally located sleeping 

 place. 



One such colony we discovered asleep on a clump of Aster 

 multiflora. The plants were two feet high, and with their low, 

 spreading branches covered an area of two by three feet. They 

 were three feet from a small creek and about ten feet from a 

 high mud bank on the other side. Although for a good many 

 evenings we examined all the vegetation in this vicinity we 

 found no sleeping Elis elsewhere. Only the males occupied this 

 bush, and only at night; they did not use it as quarters for mid- 

 day rest. 



While it was still a little light these too were shy and were 

 easily frightened away, but before night they crept back one by 

 one to their own roost. Several times each night for several 

 nights I gently stirred the bush to see them scamper off, but 

 always when I returned afte-r an absence of fifteen or twenty 

 minutes the bachelor quarters were again filled. These 

 oft-repeated disturbances did not discourage them. For a 

 period of five nights and mornings I examined this bush and saw 

 only males, but still I thought that closer examination surely 

 must show a few females present. So early one morning, when 

 just a faint streak of daylight was appearing, I found all on the 

 bush fast asleep, and with rapid sweeps of the net I took about 

 -one-third of them, 105 individuals; there was not a female 

 among them. Even while I was picking the insects out of the 

 net some of those which had escaped returned to the bush ; even 

 the commotion of sweeping the bush had not permanently 

 frightened away those which had escaped me, and the bush was 

 again teeming with inhabitants. 



The following details for 1914, both at St. Louis and in 

 Kansas, show that the sleeping conduct already recorded is not 

 due to local or environmental conditions, but that their behavior 

 is constant despite the intervention of time and space. 



On July 18, at Lake View, Kansas, another large colony was 

 discovered still asleep at 5 :30 a. m. I shook the plant vigorously 

 to note their behavior; they did not fly high in the air as they 



