Studies in Spermatogenesis Volume Ii Part 6

_Blepharida rhois_ (_Family Chrysomelidae_).

131-132. First spermatocyte, spireme stages, showing the heterochromosome group.

133-135. First spermatocyte, beginning of metakinesis.

136. First spermatocyte, equatorial plate, _x_ the unequal pair.

137. First spermatocyte, late anaphase, showing the heterochromosomes _l_ and _s_.

138. Second spermatocyte, equatorial plates.

139-140. Second spermatocyte, daughter plates of the two cla.s.ses.

_Silpha americana_ (_Family Silphidae_).

141. Equatorial plate of spermatogonium, 40 chromosomes--39 large, 1 small.

142. Resting nucleus of spermatogonium, showing 2 plasmosomes (_p_).

143-144. First spermatocyte, spireme stage.

145. First spermatocyte, prophase.

146-147. First spermatocyte, metaphase.

148. First spermatocyte, equatorial plate.

149. Second spermatocyte, equatorial plates.

150. Second spermatocyte, showing metakinesis of the small chromosome.

[Ill.u.s.tration: STEVENS PLATE XI.

N. M. S. del.

COLEOPTERA]

PLATE XII.

_Doryphora decemlineata_ (_Family Chrysomelidae_).

FIGS. 151-152. Equatorial plates of spermatogonia, 36 chromosomes--35 large, 1 small.

153. First spermatocyte, synizesis stage.

154. First spermatocyte, synapsis stage.

155-158. First spermatocyte, spireme stages.

159. First spermatocyte, spireme segmented and split.

160-163. First spermatocyte, prophases.

164-171. First spermatocyte, metaphase.

172. First spermatocyte, anaphase.

173-174. First spermatocyte, equatorial plates.

175-176. First spermatocyte, late anaphase.

177. Second spermatocyte, equatorial plates.

178-179. Second spermatocyte, telophase, _a_{1}_, archoplasmic material.

180-186. Spermatids in different stages; _a_{1}_, archoplasmic material from first spermatocyte spindle, _a_{2}_ archoplasmic material from second maturation spindle.

_Spruce-borers_ (_Family Buprestidae_).

187. First spermatocyte, metaphase.

188-189. First spermatocyte, equatorial plates of two species, 10 and 11 chromosomes.

190. First spermatocyte, anaphase.

191. Second spermatocyte, equatorial plates containing 9 large chromosomes and 1 small one.

192. Chromosomes from prophase of the first spermatocyte, all from the same cyst.

[Ill.u.s.tration: STEVENS PLATE XII.

N. M. S. del

COLEOPTERA]

PLATE XIII.

_Adalia bipunctata_ (_Family Coccinellidae_).

FIG. 193. Equatorial plate of spermatogonium, 20 chromosomes--19 large, 1 small.

194. First spermatocyte, spireme stage, _x_ the heterochromosome group.