THE EMBRYOLOGY OF THE HONEY BEE 231 



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Fig. 92. Yolk cells from eggs eighteen to twenty hours old. A, large 

 multinucleate cell, showing degenerating nuclei. B, small binucleate cell ; 

 one of the nuclei appears to be dividing by amitosis. C, small uninucleate 

 cell, x 840. 



same age, which are in all other respects perfectly normal. More- 

 over Lecaillon (1897a) has reported irregular mitotic figures in 

 the chrysomelid beetle Clytra during cleavage. It is true that 

 these figures, as stated in an earlier chapter may quite possibly be 

 caused by too slow a fixation and are therefore to be considered 

 actually abnormal. Friederichs ( 1906) however reports that 

 irregular mitotic figures are of constant occurrence in the yolk 

 cells of another chrysomelid beetle (Donacia) and are therefore 

 strictly normal. This case is precisely parallel to that of the bee. 

 Dickel (1904) also reports the occurrence of mitotic figures in 

 the yolk cells of the honey bee, but neglects to say at what stage 

 they are found. The single small figure given by him (his Fig. 

 4) indicates however that this is one of the small irregular spin- 

 dles which succeed those of the regular type. 



Examination of the text and figures of Petrunkewitsch's two 

 papers (1901 and 1902) indicates that he also probably observed 

 the small type of mitotic figures in the yolk cells but without 

 recognizing their nature. The "double nuclei" in the "Rich- 

 tungsplasma" have much the appearance of the small mitotic 

 figures when seen at a relatively low magnification. On page 28 

 of the first paper (1901) occurs the following significant para- 

 graph : "I should here also mention an observation. At the 



