Figures 250 and 251 show the first maturation mitosis as it usually appears in sections from mercuro-nitric material stained with iron-hæmatoxylin. The odd chromosome is always more or less eccentric and is attached by a spindle fiber to one pole. In Hermann material, considerably destained, the tetrads and the odd chromosome appear as in figures 252, 253, and 254, the tetrads being in position for a transverse division. The odd chromosome is always so placed that its longitudinal split is at right angles to the axis of the spindle, as though it were to divide in this mitosis. It does not do so, however, but goes to one daughter cell, always lagging behind, as is shown in figures 255 and 256. Figures 257, _a_ and _b_, are polar plates of the first mitosis with 11 and 12 chromosomes, respectively, and figures 258, _a_, _b_, and _c_, show the polar plates (_a_ and _c_) each containing 11 chromosomes, and the odd chromosome at a different level (_b_). The latter is a view of the anaphase which one often gets at three foci in one section. Figures 259, _a_ and _b_, are equatorial plates of the second mitosis with 11 and 12 chromosomes respectively. Figure 260 shows a side view of the second spindle in metaphase, and figure 261 in anaphase. Figures 262 and 263 are daughter plates from two spindles showing the chromosome content of the two equal classes of spermatozoa, one class containing 11 ordinary chromosomes, the other 11 ordinary chromosomes plus the odd heterochromosome, for the odd chromosome divides with the others in the second spindle as in Orthoptera (McClung and Sutton). In figures 264 and 265 (plate XV) are seen the telophase of the two kinds of second spermatocytes, one (fig. 265) showing the divided odd chromosome, which continues to stain more deeply after the others have become diffuse. All of the spermatids (figs. 266-268) contain, in the early stages of development, a body (_n_) which stains like chromatin, but increases in size from a small granule in the telophase (figs. 264, 265) to the large dense body (_n_) seen in figure 267. This is probably homologous with the chromatin nucleolus described for the spermatids of the Coleoptera. In addition to this, in one-half of the spermatid nuclei there is a condensed mass of chromatin which is evidently the derivative of the odd chromosome of the spermatogonia and spermatocytes (figs. 267 and 268, _x_). In common with the spermatids of other Hemiptera these show two masses of archoplasm, the larger of which forms the sheath (_s_) of the axial fiber of the tail, and the smaller the acrosome (_a_). The axial fiber grows out directly from the centrosome, on either side of which there is a dense band forming the lateral boundary of the middle piece. It will be seen that the odd chromosome of Aphrophora is in its behavior precisely like the typical Orthopteran "accessory" of McClung, and similar to the odd chromosome of the Coleoptera.