Tis BOTANICAL GAZETTE [FEBRUARY 
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35- Witson, E. B., Observations on the chromosomes in Hemiptera. Science Il. 
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EXPLANATION OF PLATES II-IV 
All the figures were drawn with the aid of a Bausch and Lomb camera lucida. 
A Zeiss 2™™ apochromat oil immersion lens was used, with Zeiss compensating 
oculars. The figures are all reduced one-half. 
PLATE II 
Oenothera lata (dominant) 
Fic. 1. arc section of a loculus of an anther; pollen mother cells in 
“resting” stage. 
Fic. 2. phe, ae stage; pollen mother cg ae from “resting” 
condition to early prophase; tapetal cells uninucleate 
Fic. 3. Later stage; pollen mother cells eae an cells binucleate, 
some of them degenerating. 
Fic. 4. Pollen mother cell denreratiog: the nucleus has disappeared and 
irregular deeply staining bodies appear in the cytoplasm. X 1500. 
