OF WASHINGTON. 327 



ate very hoggishly they still produced no rise in the temperature. 

 Another thermometer was kept in a tube a few inches away for 

 constant comparison. 



By watching some of the hungry beetles feed under the micro 

 scope, I found they ate only the fine flour-like particles, rooting 

 aside the coarser particles of bran. Possibly, if a gallon or two 

 of beetles had been tested in this way instead of one or two 

 hundred, so that the loss of heat by radiation would not have been 

 so great, a different result might have been obtained. It is well 

 known that the crowding together of bees in the hive will pro 

 duce a certain amount of heat, but certainly nothing like this ex 

 treme has been recorded, and it seems incredible that these little 

 beetles could produce so much heat in this way. I have, how 

 ever, recently found a high degree of heat produced certainly 

 30 or 40 above the surrounding atmosphere by an immense 

 number of maggots in a barrel partly filled with refuse material 

 from a slaughter-house on the Agricultural College farm. These 

 were just completing their larval stage. From the fact that in 

 every case the temperature was highest just about the time the 

 change of stage occurred (from pupa to imago, or larva to pupa), 

 it would be interesting to observe whether during this process of 

 changing, or in ordinary moulting, insects commonly produce an 

 abnormal amount of heat. I think we may expect to find that 

 during the change in the insect a certain amount of so-called 

 latent heat is changed into sensible heat, or a certain amount of 

 heat energy is expended in the operation. This seems especially 

 probable owing to the more or less complete histolysis during the 

 pupa stage. 



Discussed by Messrs. Marlatt, Austin, and Schwarz. Mr. 

 Marlatt thought that the heat was partly produced by fermenta 

 tion. Mr. Austin said he thought that it was due to the chemical 

 action of the faeces setting up the fermentation with the meal. Mr. 

 Schwarz said that the accumulation in numbers of insects pro 

 duced considerable heat, and referred to the hibernation in crowds 

 of Megilla maculata. 



MAY 4TH, 1892. 



President Riley in the chair. Nineteen persons present. 



In the absence of the Recording Secretary, Mr. Marlatt was 

 appointed Secretary pro tempore. 



Prof. H. E. Summers, of Champaign, 111., was elected a cor 

 responding member. 



