Example 1 



Preparation of a Wholemount of a Mite by the 



Method of Beriese 



The use of the name, Beriese, in the heading of this example is less an 

 injunction to employ the mounting medium of that writer than it is a tribute 

 to the method of collecting small arthropods, which he introduced. This 

 method uses the "Beriese funnel." This device is a double-walled funnel, be- 

 tween the walls of which warm water may be placed and maintained at any 

 desired temperature by applying a small flame to a projecting side arm. The 

 temperature is not critical, so that no thermostatic mechanism is provided, 

 but a thermometer may be inserted and used to read the temperature at inter- 

 vals. A circle of wire gauze with a mesh of about a sixteenth of an inch is 

 placed at the bottom of the inner glass funnel and the material that is to be 

 searched for mites is placed loosely on this gauze. The lower end of the glass 

 funnel is attached with modeling clay to a tube containing whatever medium 

 is being used for the collection of the specimens. If the specimens are to be 

 stored rather than mounted at once, % per cent alcohol may be placed in the 

 tube, and it is unnecessary to seal it at the base of the funnel. If, however, the 

 specimens are to be mounted at once in Berlese's medium, in which much 

 better mounts can be prepared from living than from preserved material, the 

 tube must contain water and be sealed to the funnel in order to prevent the 

 more active forms from working their way out of the tube. 



After the moss has been placed in position, a small lamp of not more than 

 15 watts is mounted in any kind of a reflector some distance above the mate- 

 rial. The animals in the material, therefore, find themselves surrounded by 

 heat at the sides and plagued with light from above. As all of these animals 

 are violently photophobic, they tend to move automatically toward the lowest 

 point of the moss, from which they drop down the funnel into the tube. By 

 this means it is possible in 10 or 15 minutes to collect the whole fauna from 

 a large handful of any organic material which would, by any other means, 

 take several hours to search. The use of the funnel is not confined to moss but 

 may be applied to hay, straw, shredded bark, or indeed any other material 

 from which small arthropods are customarily collected. The only difficulty in 

 using this equipment is in preventing the heat from becoming too great. Some 

 people use so large a lamp above and so high a temperature around the edges, 

 that many small arthropods are killed before rhey have time to fall into the 

 trap which has been laid for them. The author has found that the water 

 between the walls of the funnel for most uses should be at a temperature of 



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