e (fig.
28); in a front view it is a tetrad as in _T. virgata_, figure 10.
Figure 29 is the equatorial plate of a metaphase in which the larger
component of the unequal pair has been removed in sectioning. The
daughter plates of a first spermatocyte in anaphase (fig. 30) show the
separation of the components of the heterochromosome pair; and
equatorial plates of the resulting two classes of second spermatocytes
(fig. 31) show the same conditions. Figures 32 and 33 are prophases of
the second division, figure 33 showing the small chromosome ready for
metakinesis. It was impossible here also to get good drawings of
daughter plates of the second spermatocytes to show the content of the
two classes of spermatozoa, but there is no doubt that all of the
chromosomes divide in the second mitosis, giving one class of spermatids
containing the small chromosome, the other class its larger homologue.

No male somatic cells were found in mitosis, but they would, if found,
show the same conditions as in the spermatogonia. One of many good
equatorial plates from egg follicles (fig. 20) shows 30 large
chromosomes, indicating an equal pair in place of the unequal pair of
the male.

Chelymorpha argus (Family Chrysomelidae).

This species was found in larval and adult stages on _Convolvulus
arvensis_ at Harpswell, Maine, in July and August. It shows the same
conditions as _Trirhabda_ and _Tenebrio_, so far as the unequal pair of
chromosomes is concerned, and is especially favorable for study of
synapsis stages. The number of chromosomes in the spermatogonia (plate
IX, fig. 36) is 22. Here the components of the unequal pair are the
small spherical chromosome and one of the several chromosomes third in
size, forming a comparatively small unsymmetrical bivalent (figs.
47-49). The spermatogonia occupy the outer end of each follicle, and
next to them comes a layer of cysts in which the chromosomes from the
last spermatogonial division are closely massed in the form of short
deeply staining loops at one side of the nuclear space (fig. 37).
Following this synizesis stage comes one in which some of the short
loops have straightened, their free ends extending out into the nuclear
space (figs. 38 and 39). Figure 40 shows the nucleus of a slightly later
stage in which the free ends of two straightened chromosomes are on the
point of uniting. In figures 41 and 42 the point of union of homologous
chromosomes is indicated in some cases by a knob,