IO 



For permanent mounts two methods may be used with success. 

 The first is especially desirable for pupae and pupa cases, particu- 

 larly when these are provided with long dorsal wax rods, as in the 

 two species treated in this paper. A small dot of balsam is placed 

 in the center of a ring of very thick balsam, which should be three- 

 quarters of an inch in diameter and varying in height according to 

 the height of the specimen and the length of the dorsal wax rods. 

 A pupa or pupa case is then placed on the dot of balsam in the 

 center of the ring. Some annoyance may be saved by examining 

 the specimen at this time to make sure that it is uninjured. If a 

 living pupa is used, the slide should now be placed in a strong cyan- 

 ide bottle for at least fifteen minutes to insure against the mount 

 being spoiled by the emergence of the adult. A circular three- 

 quarters inch cover glass should be placed on the ring of balsam and 

 sealed, so as to make the chamber air tight. I have found chloro- 

 form balsam more satisfactory than xylol balsam for the ring, as the 

 former hardens much more quickly. If the balsam is not thick 

 enough to prevent the cover glass from settling, three cubical blocks 

 of wood of suitable size may' be imbedded in it. If preferred, zinc 

 cement may be used in the place of the thick balsam. Specimens 

 of the younger stages may be mounted in a similar manner, except 

 that they should not be fastened to the slide, and before sealing the 

 cover glass they should be gently heated over a flame, until all the 

 moisture is driven off and nothing remains but the dried bodies. 

 The results are very uncertain, however, for if the heat is applied too 

 rapidly the bodies will shrivel. 



The writer has found the following simple method the best for 

 preparing permanent mounts of the first, second and third instars. 

 Put a drop of xylol on the middle of a clean slide, remove several 

 living specimens — of all three larval instars if desired — directly from 

 a leaf and place them in the xylol. From time to time for from five 

 to ten minutes, xylol should be added to make up for the loss by 

 evaporation, and when the insects are apparently well cleared the 

 xylol can be drawn off from one side by a piece of filter paper, leav- 

 ing the specimens in the middle of the slide. A drop of thin xylol 

 balsam should now be placed immediately on the specimens, and a 

 cover glass added. If by examination with a compound microscope 

 the sides of the larvae are found to be curled inwardly, a slight pres- 



