Vol. XXX] ENTOMOI.OCICAI, N'KXVS. 



remain an acid preparation and its color will not disintegrate. 



A check series of experiments was carried out to determine 

 the action of alkali on the stain. In this series the staining 

 bath was made strongly alkaline by the addition of potassium 

 hydroxide. The results of the experiments show, conclusively, 

 that the presence of an alkali does cause the color of the stain 

 to disintegrate. In fact, when the specimens were removed 

 from the staining solution all of the color had faded from the 

 bath itself and the specimens showed no color whatsoever. 



Various strengths of staining solutions were tried in a careful 

 ami somewhat extended series of experiments. In this series 

 species of coccids with a thin cuticle, those with a medium 

 heavy cuticle, and those with a heavy cuticle were used. As 

 a result of these experiments it was found that the following 

 formula produced the best coloring in all of the species tried: 



Saurefuchsin 0.5 gram 



10 per cent, hydrochloric acid 25.0 cc. 



Distilled water 300.0 cc. 



The above formula is recommended as a solution of a stain 

 that will produce a permanent and successful color in the 

 Coccidae and their near relatives in thirty to forty minutes, 

 it can be kept indefinitely in a glass-stoppered bottle and used 

 whenever there is an occasion. 



Specimens to be stained should be removed from the potas- 

 sium hydroxide and thoroughly washed in three or four 

 changes of distilled water, then placed in a Syracuse watch- 

 glass containing a few cubic centimeters of the staining solu- 

 tion for twenty or forty minutes. After the staining is com- 

 pleted, they should be removed and treated in the manner 

 usually followed in making preparations of coccids. Saure- 

 fuchsin is not highly soluble in either carbol-xylene, clove oil, or 

 alcohol, therefore, the specimens may be left in solutions of 

 these substances a sufficient length of time to insure complete 

 clearing and dehydration. 



The explanation of the so-called fading of color in stained 

 coccids is that they are probably alkaline, and if the specimens 

 are made acid, that is to have an excess of acid present, they 

 will not become muddy or colorless. Specimens that were 

 stained, using this formula, in the winter of 1915, are at 

 the present time as brightly colored and show as much contrast 

 as they did when freshly prepared, while specimens stained 

 at the same time using a neutral solution, or one that did not 

 contain an excess of acid. ha\e become almost colorless. 



