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 classes. _Silpha americana_ (_Family Silphidæ_). 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. [Illustration: STEVENS PLATE XI. N. M. S. del. COLEOPTERA] PLATE XII. _Doryphora decemlineata_ (_Family Chrysomelidæ_). 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 Buprestidæ_). 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 Coccinellidæ_). 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 Cicindelidæ_). 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.