64 DESCRIPTION OF PLATES. 



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 (s). 



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 (n). 

 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 1 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. 



Efiilachna borealis {Family Coccinellidce). 



94. Equatorial plate of spermatogonium, 17 large chromosomes and 1 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. 



101. Unequal heterochromosome 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 i?ida (Family Scarabceidcz). 



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



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



108. Resting spermatogonium, showing plasmosome (p). 



109. First spermatocyte, spireme stage. 



