Germ-Cells in Chrysomelid Beetles. 291 



were employed in checking the results. The germ-cells stained 

 deeply in orange G, and in picric acid, and could be distinguished 

 without difficulty by their affinities for these colors. Entire embryos 

 were stained in Conklin's picro-hsematoxylin, Mayer's acid-hsemalum 

 or Partsch's alum cochineal; some remarkably clear preparations of 

 the posterior end of the egg were procured by overstaining in acid- 

 hsemalum, decolorizing in absolute alcohol containing one per cent 

 IICl, and then immediately clearing in xylol, and mounting. By 

 this method the density of the hsematoxylin was reduced and a trans- 

 parent reddish hue remained ; the granules of the pole-disc and 

 nuclear structures could be clearly distinguished in thick prepara- 

 tions after this treatment. 



Zoological Laboratory, 



The University of Wisconsin, 



April 7, 1908. 



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