ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 493 



and maltose media. lu the glucose tubes the condensation water is 

 fluorescent, and there is also a pus-like appearance of the growth. 



The organism retains its vitality:: in this medium for at least a fort- 

 night. 



Collecting and Preserving Thysanura.* — Alma D. Jackson finds 

 that one of the most successful methods for collecting alive, is to intro- 

 duce the insects (not more than two or three) into capsules, in which is 

 placed a small piece of lense paper to absorb moisture from the insects, 

 and to give them something to crawl over. The capsule may be per- 

 forated with a fine pin-point to admit air ; it is important to keep the 

 insects alive, as the antenna and body begin to shrink directly they die. 

 Another method is to use large-mouthed bottles with a funnel in the 

 neck. Pieces of wood, bark, etc., are gently tapped over the hopper, 

 and the insects fall into the bottle, which should be provided with damp 

 wood, leaves, etc., for the animals to crawl over. For fixing the insects 

 in the field, the collector should be provided with a large number of 

 small, round-bottomed phials filled with the fixative, two or three fine 

 camel-hair brushes, a large square of white oilcloth, and a chisel or pick 

 for dislodging bark or decaying wood. The pieces of bark, etc., are 

 pounded over the cloth on which the insects fall. The brush moistened 

 with fixative is placed over the insect, which, when stupefied, is easily 

 removed to the bottle. The following fixative is recommended : Glacial 

 acetic acid 1 part, absolute alcohol 1 part, corrosive sublimate to satura- 

 tion. This fixes in a few seconds, but specimens may be left on it for 

 hours, and are then transferred to 85 p.c. alcohol or gradually to glycerin 

 as follows : place the specimens on a stentor dish and add glycerin at 

 one side. After a time the cover is removed to allow the acetic acid and 

 alcohol to evaporate. 



For preserving the colour, the following fixative has advantages : 

 Glacial acetic acid 10 parts, glycerin 1— i parts, corrosive sublimate to 

 saturation. After some minutes, the acetic acid is allowed to evaporate, 

 and then the glycerin should be changed frequently to get rid of as 

 much sublimate as possible. Another method is to pom- boiling 

 absolute alcohol over the insects previously placed in a straight-necked 

 phial ; after from 5 to 15 minutes they are transferred to 95 p.c. alcohol, 

 and finally preserved in 85 p.c. alcohol. The changes between different 

 grades of alcohol should be made about every 10 or 15 minutes. If the 

 insects are to be mounted in balsam, xylol may be added gradually to 

 the absolute alcohol, or, on the other hand, glycerin may be added and 

 the alcohol allowed to evaporate. Cedar or clove oil may be used in 

 place of xylol with less liability to shrinkage. 



One of the best methods for examining Thysanura is to transfer 

 specimens which have been in glycerin for some hours to a thick syrup 

 consisting of apple-jelly and glycerin. After an hour or so they are 

 mounted in pure apple-jelly, to which a small quantity of carbolic acid 

 or of corrosive sublimate has been added. 



Specimens may also be examined in cedar or clove oil which has been 



* Ohio Naturalist, vii. (1907) pp. 119-22. 



