CLYDE C. HAMILTON. 



measured. Openings almost as large as the inlet opening may 

 be used for large flows of air and smaller openings for smaller 

 flows of air. 



The amount of air in pounds per second flowing through (C) 

 may be determined by the following formula (Durley, '06); 

 .6299 CD- 1/7/7", in which C is a constant approximately .602 

 for small openings and slight pressures, D is the diameter of the 

 opening in the diaphragm in inches, / is the inches of water dis- 

 placed, and T is the absolute temperature F. (absolute o is 

 459 F.)- The constant C varies slightly for different-sized 

 openings and different pressures, but this variation is so small, 

 however, that it may be considered as negligible in computing 

 the volume of air passing through each third of the experimental 

 cage. The diameter of the opening in the diaphragms, for all of 

 the experiments performed, was five sixteenths of an inch. The 

 static pressure was recorded in millimeters instead of inches of 

 water. By changing the millimeters to inches, substituting the 

 necessary data in the formula and solving, the volume of air in 

 pounds per second may be obtained. It was thought desirable, 

 however, to give the volume in liters of air per minute. This 

 may be obtained by multiplying the pounds per second by 60 

 to get the pounds per minute, then by 454 to get the grams per 

 minute, and dividing by 1.1265, which is approximately the 

 number of grams in one liter of air at 70 F. and a barometric 

 pressure of 29 inches. 



2. Material. 



The material studied consisted of full grown larvae and adults 

 of the family Carabidae. The following species of larvae were 

 used in the experiments: Evarthrus sodalis Lee., Harpalus vagans 

 Lee., Harpalus erytliropus Dej., Pterostichus corvinus Dej., and 

 Amara avida Say, The species of adults studied were Evarthrus 

 sodalis Lee., Harpalus erytliropus Dej., Harpalus pennsylvanicus 

 Dej., Pterostichus corvinus Dej., Pterostichus stygicus Say, 

 Amara avida Say, Anisodactylus nigrita Dej., Patrobus longicornis 

 Say, and Pntrobus placidus Say. The material was collected at 

 various times throughout the year and was kept in two-ounce 

 tin boxes partly filled with moist soil. A few of the larvae were 



