OF WASHINGTON. 27 



periods of rest, and is most active in the evening. Many Protozoa 

 are still for a long time. Dr. Gill said that the Acalephs have 

 also a resting period. Mr. Fernow said that plants also rest or 

 sleep. Their sleep is determined by the cessation of response to 

 stimulus. Mr. Schwarz spoke further of the profundity of the 

 sleep of the Hymenoptera which he had studied in Texas. He 

 took them from the plants with his fingers, and their torpor was 

 so deep that it took them some time to rouse themselves. He 

 said further that the first action of the insect on awakening was 

 to make its toilet, which he described in detail. Dr. Gill intro 

 duced the subject of hibernation and asstivation, which he dis 

 cussed at some little length. Dr. Stiles spoke of necrobiosis, 

 where rest or sleep lasts for eight or ten years. Mr. Marlatt 

 said that the habit which certain Hymenoptera have of hanging 

 by their jaws had been brought to the attention of the Society 

 before. He had noticed them in this position. It would naturally 

 be the one assumed during sleep, since to hang by the legs would 

 necessitate continued action of voluntary muscles, while the jaws 

 remain closed involuntarily. Dr. Gill described the interesting 

 habits of the African Dipnoan Protopterus which, when the 

 streams dry up, goes into the mud and makes a cocoon of slime 

 surrounded by mud and in this condition has been carried to 

 Europe and revived by placing it in water and dissolving the 

 cocoon. 



Mr. Howard read a paper on the transformations of Pulex 

 serraticeps.* 



, } - MARCH 5, i 



President Marlatt in the chair and the following members also 

 present : Messrs. Schwarz, Benton, Chittenden, Linell, Vaughan, 

 Ashmead, Casey, Heidemann, Howard, Patten, Gill, and Stiles. 



Mr. Schwarz announced the approaching completion of the 

 list of Coleoptera of the District of Columbia by Mr. H. Ulke 

 and urged that workers in other orders should now actively take 

 hold of the plan of preparing a complete list of the insects of the 

 District of Columbia. Mr. Ashmead stated that for some years 



* Published in Bulletin 4, new .series, Division of Entomology, U. S. 

 Department of Agriculture. 



