_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.
[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.
_Chlaenius aestivus_ (_Family Carabidae_).
207. First spermatocyte, spireme stage, showing the unequal pair
associated with a large plasmosome.
208. First spermatocyte, metaphase.
209-210. First spermatocyte, beginning of metakinesis.
211. First spermatocyte, equatorial plate, 17 chromosomes.
212. First spermatocyte, anaphase, showing elongated centrosome and
diverging univalent chromosomes.
_Chlaenius pennsylvanicus._
213. First spermatocyte, spireme stage.
214. First spermatocyte, equatorial plate, _x_ the unequal bivalent.
215. First spermatocyte, late prophase.
_Galerita bicolor_ (_Family Carabidae_).
216. Equatorial plate of spermatogonium, 30 chromosomes--29 large, 1
small.
_Anomoglossus emarginatus_ (_Family Carabidae_).
217. First spermatocyte, growth stage, _x_ the odd chromosome.
218. First spermatocyte, prophase.
219-220. First spermatocytes, metaphase, _x_ the odd chromosome.
221. First spermatocyte, equatorial plate.
222. First spermatocyte, daughter plates containing 18 and 19
chromosomes, respectively.
223. Second spermatocytes, equatorial plates.
_Elater I_ (_Family Elateridae, species not determined_).
224. Equatorial plate of spermatogonium, 19 chromosomes, _x_ the odd
one.
225. First spermatocyte, spireme stage, _x_ the odd chromosome.
226. First spermatocyte, metaphase.
227. First spermatocyte, prophase.
228. First spermatocyte, equatorial plate.
229. Equatorial plate from egg follicle, 20 chromosomes, _x_{1}_ and
_x_{2}_ the pair corresponding to _x_ in the spermatogonium.
_Elater II_ (_Species not determined_).
230. Equatorial plate of spermatogonium, 19 chromosomes, _x_ the odd
one.
231. First spermatocyte, spireme stage.
232. First spermatocyte, prophase.
233. First spermatocyte, beginning of metakinesis.
234. First spermatocyte, equatorial plate, _x_ the odd chromosome.
235. A pair of second spermatocytes in metaphase, two chromosomes
connected, _x_ the odd chromosome.
_Ellychnia corrusca_ (_Family Lampyridae_).
236. Equatorial plate of spermatogonium, 19 chromosomes.
[Illustration: STEVENS PLATE XIII.
N. M. S. del.
COLEOPTERA]
PLATE XIV.
_Aphrophora quadrangularis_ (_Hemiptera homoptera_).
FIG. 237. Resting primary spermatogonium with lobed nucleus.
238. Resting secondary spermatogonium, with nucleus staining much more
deeply.
239. Equatorial plate of secondary spermatogonium, 23 chromosomes.
240. First spermatocytes, very early growth stage, _x_ the odd
chromosome.
241-243. First spermatocyte, later spireme stages, showing the odd
chromosome (_x_) and a pair of _m_-chromosomes (_m_).
244. Similar stage from a safranin-gentian preparation.
245. First spermatocyte, split-spireme stage, _x_ the odd chromosome,
_m_ the _m_-chromosome tetrad.
246. Similar stage from a safranin-gentian preparation.
247-248. First spermatocyte, condensation of chromatin granules to form
tetrads in the linin spireme.
249. Later tetrad stage.
250-251. First spermatocytes, metaphase from mercuro-nitric material.
252-254. Similar stages from Hermann material, showing longitudinal
split in both the bivalents, and the odd chromosome (_x_).
255. First spermatocyte, anaphase.
256. First spermatocyte, telophase.
257. First spermatocyte, daughter plates containing 11 and 12
chromosomes, respectively.
258. First spermatocyte, _a_ and _c_ daughter plates, each containing 11
chromosomes, _x_ the odd chromosome at a different level (_b_).
259. Second spermatocyte, equatorial plates of the two classes.
260. Second spermatocyte, metaphase.
261. Second spermatocyte, anaphase.
262-263. Second spermatocyte, daughter plates of the two classes.
[Illustration: STEVENS PLATE XIV.
N. M. S. del.
HEMIPTERA HOMOPTERA]
PLATE XV.
_Aphrophora quadrangularis._
FIGS. 264-265. Second spermatocyte, telophase, showing chromatin
nucleolus (_n_) and the products of division of the odd chromosome
(_x_).
266. A spermatid containing the chromatin nucleolus (_n_).
267-268. Spermatids containing both the chromatin nucleolus (_n_) and
the odd chromosome (_x_), _a_ the acrosome.
269. Equatorial plate from a somatic cell of a male larva, 23
chromosomes.
270. Equatorial plate of an oogonium, 24 chromosomes.
271. Resting nucleus of a young oocyte before synapsis, showing two
pairs of condensed chromosomes, corresponding in size to the
_m_-chromosomes and the odd chromosome of the spermatocytes.
272-277. Sections of nuclei of oocytes, showing one or more of these
heterochromosomes, from safranin-gentian preparations.
278-279. Bouquet stage from iron-haematoxylin preparations, showing the
heterochromosome bivalent (_x_).
_Cacoecia cerasivorana_ (_Lepidoptera_).
280. First spermatocyte, synizesis stage, showing 2 condensed
chromosomes (_x_{1}_ and _x_{2}_).
281-282. First spermatocyte, synapsis stage.
283-284. First spermatocyte, growth stages.
285. First spermatocyte, prophase.
286-287. First spermatocyte, later prophases, showing the
heterochromosome pair (_x_).
288. First spermatocyte, metaphase.
289. Second spermatocyte, metaphase.
290. First spermatocyte, equatorial plate.
291-292. Second spermatocyte, equatorial plates.
_Euvanessa antiopa_ (_Lepidoptera_).
293. First spermatocyte, equatorial plate.
[Illustration: STEVENS PLATE XV.
N. M. S. del.
HEMIPTERA AND LEPIDOPTERA]
End of Project Gutenberg's Studies in Spermatogenesis, by Nettie Maria Stevens