122 Psyche [June 



In the above-mentioned paper we (7) called attention also to 

 certain indications which appear a day or two before Diapher- 

 omera molts. A method, which instantly revealed to us when the 

 walking-stick had molted, was to first mark them with a tooth- 

 pick, match or needle dipped in water-proof India ink. A few 

 hours after each molt, some difficulty maj' be experienced in mark- 

 ing the specimens, for the ink may not then spread evenly but may 

 run together to form drops, as if the newly exposed integument was 

 oily. This may be due to the molting or exuvial fluid which forms 

 between the old and new skins at the time of ecdysis. If, however, 

 the integument has thoroughly dried, no trouble will be encountered 

 in marking the walking-sticks. Sometimes after a week or more, 

 the India ink will wear or peel off, but this can be replaced very 

 readily by a second coating. 



In our experiments, the walking-sticks were reared to maturity 

 in a large glass jar covered with a glass plate. Five young walking- 

 sticks were usually placed in each jar, these insects being first 

 marked with India ink on the dorsal side of one of the three divi- 

 sions of the thorax or the anterior or posterior halves of the abdo- 

 men. At the bottom of the jar rested a small narrow-mouthed 

 bottle filled with water, in which had been placed a few twigs of 

 hazel-nut or linden leaves. If a wide-mouthed bottle was used, 

 the top was closed around the twigs, for the young walking- 

 sticks in wandering about, as well as during the process of molting, 

 will otherwise often fall into the water and drown. The water 

 in the bottles was either changed every day or the loss of water 

 from the bottles due to evaporation or to transpiration of the 

 leaves was replaced with fresh water through a long pipette. 

 All the leaves attacked by fungus or bacterial diseases were 

 removed from the twigs; and the jar as well as the leaves were 

 freed daily from all excrement. Fresh twigs of hazel-nut or linden 

 leaves, first carefully washed in water, were supplied about twice 

 a week. The moisture which condensed in the jar was removed 

 whenever drops were formed, especial care in this respect being 

 exercised when the walking-sticks were very young, for otherwise 

 many specimens were found sticking to the glass jar. By keeping 

 the jars away from open windows, the condensation of the water 

 was greatly reduced. 



To hatch the leaf-insect, Phyllium scythe (Gray), Morton (5) 



