J 6 9 10 II 12 J 14 15 16 I 16 19 20 



13 17 



Plate XVI 



No. 28 The effect of stretching a salivary chromosome of Chironomiis plumosus 

 by micromanipulation, x 850. From Buck J. Hered. 32 (1942) 10 {By 

 courtesy). The needle points are indicated by V. The numbers indicate 

 positions of same individual bands in successive figures, a unstretched, b-e 

 elongated 20°o (b), 8o°o (c), i75°o (d)^ 300% (e) ; f relaxed again. Notice 

 that most of the elongation is in the interband regions which become 

 longitudinally striated. 



