April, 1907.] Collecting and Preserving Thysanura. 121 



proceeded for some time the glycerine should be changed fre- 

 quently in order to dispense with as much corossive sublimate 

 as possible. 



BoiLiXG Absolute Alcohol. — This is another method 

 which is particularly applicable for laboratory use. Place the 

 specimens in a straight necked vial and pour over them boiling 

 absolute alcohol. Leave for from five to fifteen minutes and 

 transfer to 95% alcohol, and preserve permanently in 85%. 

 The specimens when properly fixed may be left in this grade 

 indefinitely without shrinking. The changes should be made 

 between the chfferent grades of alcohol about every ten or fifteen 

 minutes. If it is desired to mount the specimens in balsam, 

 xylol may be added gradually to the absolute alcohol. Or on 

 the other hand glycerine may be added and the alcohol allowed 

 to evaporate. The alcohol may be used cold in the same man- 

 ner as described above ; however, there is less liability of shrink- 

 ing the specimens if the temperature is raised to the boiling 

 point. No more time should be occupied in transferring the 

 specimens from alcohol to balsam than is ablsoutely necessary 

 however, if the transfer is made too rapidly the specimens will 

 cloud. Cedar or clove oil may be used in place of xylol with less 

 liability of shrinkage. While balsam mounts are almost always 

 shrunken thev are almost indispensable for the detailed study of 

 the claws, spring, and hairs of the insect. 



Sugar Jelly Mouxtixg Media. — One of the best methods 

 for examining the Thysanura is as follows: Specimens that 

 have been in pure glycerine for a few hours are placed in a thick 

 svrup consisting of apple jelly and glycerine. After staying in 

 this syrup for an hour or so they are mounted in pure apple 

 jelly in which a very small amount of carbolic acid or corossive 

 sublimate has been added. The clearest jelly possible should 

 be selected, melted, and a few drops of carbolic acid or corossive 

 sublimate stirred, in and then filtered through two or three 

 folded filters. The cover glass should be rung with some gcol 

 cement. Bell's having proved most satisfactory, and afterwards 

 finished with black enamel. This is a method that has been 

 tried and found successful for mounting Papirius, and is the only 

 means bv which I have Vjeen able to preserve both their form 

 and color. However, the utmost care must be observed through- 

 otit, giving the fixing agents plenty of time or the specimens will 

 shrink destroying their correct form and color. 



Specimens mav also be examined in pure cedar or clove oil 

 which has been boiled down to a thick syrup. The only way 

 such slides can be finished is by ringing them with Bell's cement. 

 This method is excellent for showing some of the finer details. 



Live boxes for these minute insects are very easily and simply 

 constructed, when one wishes to study their habits in the lab- 



