326 PROCEEDINGS OF THE ACADEMY OF [April, 



Fig. 110 — First spermatocyte, later growth stage, double plasmosome, 



centrosomes divided and ciliated. 

 Fig. Ill — First spermatocyte, segmented spireme, segments opening into 



rings. 

 Figs. 112-115 — First spermatocyte, stages in the formation of dyads and 



tetrads of prophase. 

 Fig. 113 — First spermatocyte, formation of chromatin-plasmosome. 

 Figs. 116 and 117 — First spermatocyte early metaphase. 

 Fig. 118 — First spermatocyte, equatorial plate. 31 chromosomes. 

 Fig. 119 — First spermatocyte, metaphase spindle. 

 Fig. 120 — First spermatocyte, anaphase spindle. 

 Fig. 121 — First spermatocyte, telophase. 

 Fig. 122 — First spermatocyte, telophase, polar view. 

 Fig. 123 — Second spermatocyte, arrangement For second division. 

 Fig. 121 — Second spermatocyte, equatorial plate, 31 chromosomes. 

 Fig. 12.5 — Second spermatocyte, metaphase spindle. 

 Fig. 126 — Second spermatocyte, anaphase spindle. 

 Fig. 127 — Second spermatocyte, telophase. 

 Fig. 12S — Spermatid, iirst stage. 

 Fig. 129 — Spermatid, second stage. 

 Fig. 130 — Spermatid, later stage, formation of axial filament. 



Plate XXVI — Automeris io — Figs. 131-135 — Spermatids, later stages, showing 

 development. 

 Fig. 136 — Spermatids, c. s. through axial filament and membranes. 



Samia cecropia — Figs. 137 and 139 — Spermatogonial stages, rest stage showing 



plasmosome. 

 Fig. 139 — Spermatogonial stages, metaphase spindle. 

 Fig. 140 — Spermatogonial stages, anaphase spindle. 

 Fig. 141 — Spermatogonial stages, telophase. 

 Fig. 142 — First spermatocyte, formation of spireme, preparatory to syn- 



ezesis. 

 Fig. 143 — First spermatocyte, smear showing granular thread of synezesis. 

 Fig. 144 — First spermatocyte, early post-synapsis. 

 Fig. 145 — First spermatocyte, later post-synapsis. 

 Fig. 146 — First spermatocyte, late post-synapsis. 

 Fig. 147 — First spermatocyte, growth stage, showing plasmosome and 



chromatin granule. 

 Fig. 148— First spermatocyte, growth stage, smear preparation, showing 



identity of chromosomes. 

 Figs. 149-152 — First spermatocyte, formation of dyads of prophase, 



formation of a chromosome from a chromatin-plasmosome. 

 Fig. 153 — First spermatocyte, equatorial plate. 30 chromosomes. 

 Fig. 154 — First spermatocyte, metaphase spindle. 

 Fig. 155 — First spermatocyte, anaphase spindle. 

 Fig. 156 — First spermatocyte, telophase spindle. 



Fig. 157 — First spermatocyte, telophase, polar view, chromosome scattering. 

 Fig. 158 — First spermatocyte, telophase, polar view. 



Figs. 159 and 160 — Second spermatocyte, arrangement for second division. 

 Fig. 161 — Second spermatocyte, equatorial plate, 30 chromosomes. 

 Fig. 162 — Second spermatocyte, metaphase. 

 Fig. 163 — Second spermatocyte, anaphase. 

 Fig. 164 — Early spermatid. 

 Fig. 165 — Spermatid, second stage. 



Plate XXVII — Samia cecropia — Fig. 166 — Spermatid, second stage. 

 Figs. 167-169 — Spermatid, later stages. 

 Fig. 170 — Spermatozoon , vibratile filament, J its length. 



Acronycta sp.,?— Figs. 171 and 172— First spermatocyte, growth stage showing 

 "chromosome granule" and mitochondria. 



