4O F. G. HALL. 



were dropped into water after exsiccation small air bubbles arose 

 as the leeches uncoiled. After extreme exsiccation the leeches 

 became hard ; the skin dry ; all mobility and elasticity were lost ; 

 and a mucus secretion enveloped the body, as was the case with 

 the earthworms. During recovery the body, posterior to the 

 twelfth segment, became swollen and was apparently inactive. 

 The anterior part of the body remained active. The posterior 

 part of the body became swollen to twice its natural size and 

 softened. After a few days it broke open and the animal ap- 

 parently bled to death. Leeches usually showed signs of recovery 

 within an hour after removal from the exsiccation chamber to 

 water. 



The results of these experiments, with twenty individuals, 

 show: (i) leeches were exsiccated to 70.4 per cent, of their body 

 weight, or approximately 92 per cent, of the water contained in 

 the body was given up, without loss of vitality; (2) lower tem- 

 peratures were more favorable to the recovery of the exsiccated 

 leeches. 



Meal Worm. 



The meal worm, the larva of Tenebrio molitor Linn., was used 

 The methods employed were the same as with the earthworm. It 

 was very difficult to tell when the vital limit of exsiccation was 

 reached as the meal worms were inactive for the greater part of 

 the time while in the exsiccating chamber. One meal worm lost a 

 greater percentage of body weight than the average percentage of 

 water contained in the body. The body of the meal worm con- 

 tains much fat. It is probable that metabolic water was derived 

 from this fat during exsiccation. The body of a meal worm al- 

 ways 'became considerably compressed during exsiccation. 



The results of these experiments, with ten individuals, show : 

 (i) meal worms were exsiccated to 52.6 per cent, of their body 

 weight without loss of vitality; (2) the weight lost was greater 

 than the average weight of water contained in the body; (3) the 

 chitinous integument is probably a factor in offering resistance 

 to evaporation. The meal worms endured exsiccation for a con- 

 siderable length of time. 



