1916] The Sleep of Insects 233 



I then decided to mark them to ^ee whether the insects 

 coming each evening were really the same ones. It was very 

 near dark, and an inartistic piece of work it was, but they must 

 have been in deepest sleep, for they were motionless while I 

 applied the paint. At midnight not one of them had moved an 

 iota, and they were so lost in slumber that when the candle was 

 brought very near to them it aroused not the sHghtest response. 

 The next morning found them in the same position ; one by one 

 they awoke, rubbed their antennas as a sleepy child rubs his 

 eyes, and independently flew away without ado, the last one 

 leaving at 7:30. 



At 4:30 that afternoon, (July 16), a vigilent watch was 

 begun to see if the marked individuals would return, and if so 

 whether they would come in a body or singly as they had gone 

 forth. At 5:30 one wasp arrived. and a half-hour later two 

 more. Two were marked insects, and the third was a 

 stranger. All hovered about from twig to twig and sometimes 

 flitted off to other bushes for a brief sojourn, but the two marked 

 individuals returned frequently to their favorite spray. At 

 dusk the two were settled and ready for sleep in the accustomed 

 place, but the stranger, probably finding the situation not to his 

 liking, sought other quarters and was seen no more. The next 

 morning the two sleepers were just as I had left them. That 

 night the incidents were repeated in every detail, the two marked 

 wasps (they were females) finally remaining and the stranger 

 departing. On the succeeding night, however, only one of the 

 marked wasps appeared to spend the night in the accustomed 

 spot. Again a stranger, perhaps the one already mentioned, 

 accompanied her and in the usual fastidious manner examined 

 the twigs and found the place unsatisfactory and hied itself 

 to another berth. 



The next evening, July 19, the two marked wasps and the 

 guest again returned and all of them again buzzed about their 

 particular green cluster, and as usual the stranger departed. 

 But the two old residents this time sought a place on two dis- 

 tinct bushes. A new situation had arisen this evening, however ; 

 a lot of disgusting, newly-hatched Hemiptera {Anasa tristis) 

 were actively occupying the favorite spray. Hence we cannot 

 be surprised that the two wasps, finding their abode usurped 

 and their peace disturbed, departed after a short visit to other 

 bushes. The one which had spent the night elsewhere gave no 

 evidence to account for its wanderings. 



