PREPARATION 



15 



be found very convenient at times for handling, transferring, and 

 cleaning specimens. 



Clarifying. The removal or dissolving of the wax excreted 

 by all or certain cells of the hypodermis and the making of the 

 body translucent is known as clarifying. This can be accomplished 

 by the use of several substances, the best of which is a solution of 

 caustic potash. 



The body of the insect or the wax surrounding it is usually 

 closely attached to the host-plant. It must be detached in such a 

 way as not to injure the finer microscopic parts which are fre- 

 quently located along the margin of the body. This margin is 

 ordinarily distinct since the body is generally more or less 

 depressed in the adult female. In many species the characters 

 used for differentiation are the presence and absence and form 

 of minute setae or setae-like projections which are easily destroyed. 

 The specimens should be separated from the host-plant with a fine 

 dissecting needle under a binocular or simple microscope or a hand 

 lens. Where the body is encased in a homogenous mass of wax, 

 this should be placed directly into the clarifying solution. In the 

 Diaspidinae the body of the insect is covered by a composite 

 scale consisting of wax excreted by the insect and one or two cast 

 nymphal exuviae which are imbedded in the wax. The body of the 

 insect is located beneath the scale and can be exposed in most 

 cases by simply turning the scale over. In certain species the body 

 can be separated from the scale only with great difficulty, this is 

 due to the presence of a pronounced ventral scale. Where it is 

 difficult to separate the insect from the scale, the scale and the 

 enclosed insect should be placed in the clarifier. When the insect 

 is exposed, the dried body should not be lifted or handled by 

 holding it between the file-like or even smooth points of a pair 

 of forceps. Moisten the point of the dissecting needle or of the 

 forceps with water, alcohol, or caustic potash, or on the tongue and 

 lift the specimen with the moistened tool. It is frequently 

 desirable to mount some of the nymphal exuviae of the female 

 attached to the scale, since they frequently show characters not 

 found on the body of the insect itself. In certain genera of the 

 Diaspidinae the last or second nymphal exuvia is not molted and 

 it must be broken open to obtain the body of the insect. 



The best solvent of the wax is a solution of caustic potash. 

 It is also the best substances for expanding the body and making 

 it translucent. A ten per cent solution, made by adding ten grams 

 of stick potash to ninety cubic centimeters of distilled water, is 



