MITE IN BERLESE'S MEDIUM 83 



run down inside. When this has been done, the tube is removed, and the con- 

 tents are tipped out into a petri dish or similar container, ready to be mounted. 

 The specimens are best collected with the aid of a fine brush which is moistened 

 in water. 



A mite or similar form which is to be mounted is selected, picked up on 

 the tip ot the brush, and transferred to a drop of whichever of the two gum 

 media has been selected. As little water as possible should be transferred with 

 it, and the mite should be pushed under the surface of the gum with the point 

 of a needle. The mount is inspected under the low power of the microscope, 

 and, if any large quantity of air has been carried in with the mite, the bubbles 

 are released with the aid of a fine needle and allowed to come to the surface 

 before the coverslip is laid gently into place. The drop of gum should be large 

 and no endeavor should be made to press the coverslip down. If a reasonably 

 thick layer of mountant is left, almost any small arthropod will spread its legs 

 like a textbook diagram before dying and will remain in this form indefinitely. 

 As soon, therefore, as each mount has been made, it is pushed aside, and the 

 next specimen is mounted, so that in a remarkably short space of time one 

 has permanent records of all the small arthropods which were present. The 

 finishing of these slides has already been discussed and may be carried out at 

 any time after they have been made. 



Summary 



1. Erect Berlese funnel. 



2. Transfer small arthropods to drop of mounting medium on slide. 



3. Add coverslip. 



