In figure 184 a polar view of a metaphase is shown, the unequal pair, which was somewhat below the others, being indicated by stippling. Figures 184 _a_ and 185 show that the unequal components of the unsymmetrical pair, as well as the equal components of the symmetrical pairs, are separated in metakinesis, making this clearly a reduction division. Two polar plates are shown in figures 186 and 187, one containing 10 equal elements, the other 9 equal ones and 1 small one. The telophase is shown in figure 188. There is no resting stage, but the new spindle is formed from the remains of the old one, and the spindle-shaped mass of chromatin seen in figure 188 either passes into the center of the new spindle or becomes enveloped by it. The double chromosomes separate as in figures 189 and 190. Figure 190 shows the small dyad, and figure 189 an aberrant one which may be its mate. The spindle in both divisions is peculiar in having outside of the spindle proper a dense mass of fibers which, in osmic material, stain deeply with iron haematoxylin. These fibers are shown in all the figures from 174 to 196. Figures 191 and 192 are equatorial plates of the two kinds of spermatocytes of the second order, figure 191 showing the small chromosome. An early anaphase appears in figures 193 and 194, which show both the small and larger chromosomes in metakinesis. Figure 195 is a later anaphase containing the divided small chromosome. In figure 196 are shown the two polar plates of a spindle corresponding to that of figure 195, and in figure 197 the polar plates of a spindle in which 10 equal chromosomes have been divided. In _Tenebrio molitor_ the spermatids are therefore certainly of two distinct kinds, so far as the chromatin content is concerned. In most of the young spermatids, after the nuclear membrane has formed, there appears an isolated chromatin element, which corresponds fairly well to the large or to the small component of the unsymmetrical pair, separated in the first mitosis and divided in the second. The clear portion of the nucleus containing this isolated element is at first turned toward the spindle-remains (fig. 198), but before the tail appears either the whole nucleus or its contents have rotated 180 deg. (fig. 199). Various stages in the development of the spermatid are seen in figures 200 to 203. The clear region and the isolated element finally disappear (fig. 202 _b_), and the chromatin breaks up into coarser and then into finer granules within the sperm-head. In the later stages the centrosome is clearly seen at the base of the head (fig. 203).