64 DESCRIPTION OF PI.ATES. 



Plate X. 

 Odontota dorsalis. 



Figs. 69-70. First spermatocyte, metaphase. 



71. First spermatocyte, equatorial plate. 



72. First spermatocyte, metaphase, showing metakinesis of the heterochro- 



mosomes. 

 73-74. First spermatocyte, anaphase. 

 75-76. Second spermatocyte, equatorial plates. 



77. Second spermatocyte, showing metakinesis of the small chromosome (5). 



78. Second spermatocyte, prophase, showing chromosomes longitudinally 



split. 

 79-80. Young spermatids, n the chromatin nucleolus. 



81-87. A series of stages in the development of the sperm head, showing the 

 various phases in the history of the chromatin nucleolus («). 

 88. Cross-sections of nearly mature sperm heads. 

 89-90. Equatorial plates of spermatogonia of abnormal individual, 15 large 

 chromosomes, 2 small ones. 

 91.. First spermatocyte from same testis, spireme stage, showing 2 small 

 chromosomes associated with i large one and a plasmosome. 



92. First spermatocyte from the same testis, metaphase showing a similar 



heterochromosome group. 



93. Second spermatocyte from same testis, equatorial plate, showing 2 small 



chromosomes. 



Efilachna borealis (Family CoccineUidce). 



94. Equatorial plate of spermatogonium, 17 large chromosomes and i small 



one. 



95. First spermatocyte, spireme stage, showing the unequal pair. 

 96-97. First spermatocyte, late prophases. 



98. First spermatocyte, metaphase, showing chromosomes of different forms. 

 99-100. First spermatocyte, equatorial plate. 



loi. Unequal heterochromos6me pair from a metaphase. 



102. First spermatocyte, anaphase; ordinary chromosomes stippled to show 



more clearly the metakinesis of the unequal pair. 



103. Second spermatocyte, equatorial plates. 



104. Second spermatocyte, prophase. 



105-106. Abnormal giant spermatids, probably in process of degeneration. 



Euphoria inda (Family Scarabceidce), 



107. Equatorial plate of spermatogonium, 20 chromosomes. The 2 smallest 



are the unequal pair of heterochromosomes (I and s). 



108. Resting spermatogonium, showing plasmosome (/). 



109. First spermatocyte, spireme stage. 



