m the chromosomes, as in many
cases in oogenesis, one can only surmise.

In one testis a peculiar abnormality was found. In all of the perfect
spermatogonial plates two small chromosomes were present (figs. 89, 90).
Nineteen such plates were counted in five different cysts. All of the
equatorial plates of the first spermatocytes showed 8 chromosomes, as
usual. In a few favorable growth stages (fig. 91) the two small
chromosomes were seen to be combined with the larger heterochromosome
and a plasmosome, and one first spermatocyte spindle was found in which
the same combination could be clearly seen (fig. 92). All of the second
spermatocyte metaphases in which a small chromosome occurred, contained
two small ones, making 9 in all (fig. 93). The others contained 8 large
chromosomes, as usual. The only explanation suggested by the conditions
is that somewhere in its history, the small chromosome had undergone an
extra division, and that ever afterward the two products behaved like
the one small heterochromosome of a normal individual. The chief
interest in this abnormality centers in the fact that the two small
chromosomes of this specimen behave exactly like the usual single one,
emphasizing the individuality of this particular heterochromosome. Both
evidently have the same individual characteristics and affinities as the
one in other cases.

Epilachna borealis (Family Coccinellidae).

_Epilachna borealis_ was found in abundance on squash vines at Woods
Hole, Massachusetts, in September. The testes, unlike those of most of
the Coleoptera, consist of many free follicles similar to those of the
Orthoptera. The germ glands were rather far advanced, but some good
spermatogonial and spermatocyte cysts were found. In figure 94, a
spermatogonial metaphase, the small chromosome is shown with 17 larger
ones. The heterochromosome pair appears in condensed form in the spireme
stage (fig. 95), and again in the first maturation spindle (figs. 96,
97). The varying forms of the ordinary chromosomes are shown in figure
98. Figures 99 and 100 are equatorial plates of the first mitosis. The
unequal pair is shown by itself in figure 101, and the separation of the
heterochromosomes is seen in figure 102. Equatorial plates of the
second division, one containing the small chromosome (_b_), are shown in
figure 103. A prophase of the same division (fig. 104) proves that the
small chromosome divides quantitatively like the others. It was
inte