• DESCRIPTION OF PLATES 



The figures were all drawn with a Zeiss 1.5 mm. oil immersion objective and a Zeiss compensating 

 ocular 12. The magnification was doubled with a drawing camera, and the plates reduced one-half, 

 giving a magnification of 2000 diameters. 



Lettering on Plates 

 p = 3. plasmosome 

 X = the unpaired heterochromosome 



Pl'vte I 



Green rose aphid 



Figs. I to 3 First spermatocyte, anaphase. 



Fig. 4 Second spermatocyte, large, prophase, seven chromosomes. 



Fig. 5 Second spermatocyte, small, prophase, six chromosomes. 



Fig. 6 First spermatocyte, metaphase. 



Fig. 7 Second spermatocyte, metaphase. 



Fig. 8 First spermatocyte, metakinesis. 



Star cucumber aphid 



Fig. 9 First spermatocyte, early anaphase. 



Fig. 10 First spermatocyte, telophase. 



Figs. II and 12 Second spermatocyte, large, prophase, five chromosomes. 



Fig. 13 Second spermatocyte, small, prophase, four chromosomes. 



Fig. 14 Second spermatocyte, large, metaphase, five chromosomes. 



Fig. 15 Second spermatocyte, small, metaphase, four chromosomes. 



Aphid from Solidago altissima 



Fig. 16 First spermatocyte, prophase, possibly a synizesis stage. 



Fig. 17 First spermatocyte, metaphase. 



Figs. 18 and 19 First spermatocyte, lateral view of chromosomes in metaphase. 



Fig. 20 First spermatocyte, anaphase. 



Figs. 21 and 22 First spermatocyte, telophase. 



Fig. 23 Second spermatocyte, large, prophase, six chromosomes. 



Fig. 24 Second spermatocyte, large, metaphase, six chromosomes. 



Fig. 25 Second spermatocyte, small, metaphase, five chromosomes. 



Aphid from beach goJdenrod 



Fig. 26 First spermatocyte, anaphase. 



Fig. 27 First spermatocyte, telophase. 



Fig. 28 First spermatocyte, metaphase. 



Fig. 29 Second spermatocyte, large, prophase, six chromosomes. 



