The follicles of the cricket testis show the different cell generations and the same relative arrangement of them as McClung (’00) found in _Hippiscus_, and Sutton (’00) in _Brachystola_. The spermatogonia are nearest the blind end of the follicles, spermatocytes next, and the spermatids following the latter. The cells of a cyst are not, as in _Anasa_ (Paulmier, ’99), “in the same stage of development,” but only approximately so, for some cysts show cells in the metaphase, while others have reached the telophase. Successive cysts, as in _Brachystola_, do not show successive stages; for, frequently, growing spermatocytes and late spermatids, or even young spermatozoa, were observed side by side. The individual cells in division pass through prophases, metaphases, anaphases, and telophases—these terms being used according to their usually accepted meanings. (See McClung, ’00.) In this paper I shall begin with the cell when it has reached the telophase of the second spermatocyte division; that is, just after the chromosomes have reached the poles of the spindle. III. Observations. (_a_) THE NUCLEUS. The chromatin in _Gryllus_ behaves very much as Henking (’91) has described for _Pyrrhocoris_, and Paulmier (’99) for _Anasa_. At the end of the anaphase the chromosomes are crowded together at the poles of the spindle. (Fig. 1.) A clear space begins to be formed around them, especially on the equatorial side. (Fig. 2.) They then separate and are scattered somewhat evenly over the nuclear membrane when it is formed, as seen in figs. 4, 5, and 6. Soon protuberances appear on the surface of the individual chromosomes, making their outlines irregular. At about this time they begin to show a granular structure. The chromosomes break up more and more, and soon the chromatin appears in irregularly arranged patches or blotches of granules of various sizes. (Fig. 8.) Meanwhile the nucleus has slowly increased in size. It reaches its maximum, which is probably about treble its original diameter, before the cell begins to elongate. The granules have been breaking up into finer and finer pieces, until, a little after the cell has reached its maximum, the chromatin has largely disappeared, or, to be more exact, has lost its affinity for stains. (Fig. 16.) As the cell begins to elongate, the nucleus goes to one end, namely, that toward the periphery of the cyst. (Figs. 14 and 15.) The chromatin again frequently appears in patches as the cell decreases in size. (Figs. 33 and 36.) In many cells the patches never disappear. When it has diminished to less than half its maximum diameter, the nucleus begins to elongate, becoming elliptical, and finally forms the long, tube-like head of the spermatozoon. (Figs. 43 and 45.)