PLATE X 



Figs. 1-5. — Meiosis in Phragmatobia fuliginosa, Lepidoptera. (From 

 Seller, 1925.) 



Fig. I. Fragmented race, male, n = 29. Fig. 3. Fused race, 

 male, n — 28. Figs. 2, 4 and 5. H^^biid between the two races, 

 male, showing pairing of two small chromosomes with one large one. 



Fig. 6. — First metaphase in Melandrium album, male : pairing of X 

 and Y. (From Belar, 1925.) x ca. 1000. 



Fig. 7. — First metaphase in Zea Mays, monosomic shoot of a diploid 

 plant, showing 9 bivalents and i univalent. X 650. (From 

 McClintock, 1929 h.) 



Figs. 8 and 9. — Polymitosis in Zea Mays pollen grain. 



Fig. 8. Late prophase. Fig. 9. Metaphase. Two chromosome 

 pairs, probably with interstitial chiasmata in each nucleus. (From 

 Beadle, 1931.) X 650. 



