l plates.

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

[Illustration: 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.

[Illustration: 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.

195. First spermatocyte, metaphase.

196. First spermatocyte, equatorial plate.

197. Second spermatocyte, equatorial plates.

_Cicindela primeriana_ (_Family Cicindelidae_).

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

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

200. First spermatocyte, prophase.

201. First spermatocyte, metaphase, _x_ the unequal pair in tripartite
form.

202. First spermatocyte, showing metakinesis of the heterochromosomes
(_l_ and _s_).

203. First spermatocyte, equatorial plate.

204. Second spermatocyte, equatorial plates.

205. Giant spermatocyte, spireme stage, heterochromosome group double
the usual size.

206. Giant spermatocyte, prophase.

_Chlaeni