1916] The Sleep of Insects 



259 



Diabrotica vittata Fab. 

 _ I hardly think that these striped pumpkin beetles sleep dur- 

 ing the night; at least many of them were active in the jimson 

 blossom at 9:30 p. m. on August 15 at Lake View, Kansas The 

 next mornmg at 6 o'clock many of them were still in the blos- 

 soms, but I can offer no guarantee that they were the same 

 individuals. Again at 5:50 a. m. on August 16 and 17 I found 

 from two to seven individuals of this species in each of twenty 

 pumpkin blossoms. Many of them were in copulo Since 

 these flowers do not open until early morning, this is evidence 

 that they must have been awake and migrated during the night. 



Copris Carolina Linn. 

 Just after dark July 29, we followed the sound of a heavy 

 buzzing msect and turned our Hght upon a flying Copris Carolina 

 It was hovermg m the road above a pile of fresh horse-dung. 



Canthon laevis [E. A. Schwarz]. 

 This dung roller was often seen during the day buried under 

 soft dung; sometimes it was abroad at night, up to 11-30 p m 

 rolhng and burying its ball. The periods of rest are very irreg- 

 ular, but since the animal goes into the burrow with its food 

 ball and sits at table until all is eaten, perhaps sufficient periods 

 of rest occur at these times. 



Harpalus ruficomis [E. A. Schwarz]. 



Harpalus pennsylvanicus [E. A. Schwarz]. 



Harpalus caliginosus [E. A. Schwarz]. 



One can scarcely stroll out over a pasture field on a summer 



evening after dark without being greeted by these active 



beetles on the wing or ambHng along the path or scrambhng 



through the grass. But on a cold, damp September evening 



we have found H. ruficor?iis in their holes. Perhaps they all 



sleep m their holes at one time or another, just as it suits their 



convenience. 



Limonius agonus Say. [E. A. Schwarz]. 

 June 10, at 10 p. m. two of the small brown cHck beetles so 

 common here at St. Louis were calmly at rest on a leaf of 

 poison ivy. I could not discern whether they were asleep. 



