16 THE COCCIDAE 



the best strength to use. The effect of a very strong solution is 

 different from that of a weak solution which destroys the cellular 

 structures. Distilled water should alwaj's be used in making the 

 solution, if this is not available, fresh rain water should be used. 

 Water containing lime or tap water that has been filtered with 

 chemicals should never be used in making a solution of caustic 

 potash or used in washing specimens. When such water is used, 

 the various chemicals form linear or spine-like crystals in the 

 specimens. It is often desirable to use a weaker solution than ten 

 per cent, such a solution can readily be made by diluting the stock 

 solution one-half, one-third, or one-fourth as desired, making about 

 five or three or two per cent solutions. 



In large species and those with globular bodies, it will often 

 be found desirable to separate the dorsal and ventral surfaces and 

 mount the two portions side by side under the same cover-glass. 

 Large species after they have been boiled for a time often have 

 large opaque masses within them. The body in such cases should 

 be punctured and the hard opaque mass removed. The source of 

 these masses is not known. If the specimen is left in the caustic 

 potash until the mass is dissolved, the specimen will be ruined. 

 The time necessary for the clarification of any particular species 

 varies with the individual. Some specimens of a species will clear 

 (luickly while others will take considerable time. The specimens 

 should at all times be given careful attention. The length of time 

 required will need to be modified Avith each species. This can 

 be determined only by observing the rapidity of the clarification. 



Those specimens in which the body is soft or the cuticle is 

 thin must be handled carefully so as not to puncture or tear the 

 cuticle unnecessarily, but particularly so as not to get the body 

 out of shape. This applies especially where the body is bag-like 

 in form. Species that norraalh^ have the body depressed are liable 

 to become distorted or decidedly compressed. Many specimens 

 become so distorted that considerable time is required to unravel 

 the relation of the various parts. This distortion is due to one 

 or both of two causes, carelessness in handling the specimens with 

 the forceps or carelessness in boiling them too vigorously, frequently 

 the latter. Specimens that are badly distorted, unless tliey are 

 very rare, are not worth the time required to mount them. When 

 the caustic potash for clarifying or the water for washing is boiled 

 vigorously, the specimens are forced to the surface of the liquid 

 and into the greatly agitated surface film. This has the effect of 

 flattening out the specimens, folding them compactly, and twisting 



