toxylin. In
section 278 the "bouquet" was cut through, showing the bivalent
corresponding to the larger pair in figure 271, and in figure 279 this
element is seen behind the paler loops. The history of these two pairs
of heterochromosomes, which have not, so far as I know, been found
before in oocytes, should be followed up in older ovaries, and related
species should be examined for similar phenomena.

LEPIDOPTERA.

Cacoecia and Euvanessa.

I had no intention of making an extended study of the spermatogenesis of
the Lepidoptera, but was interested to see if anything corresponding to
the heterochromosomes of other orders could be found. The material
studied was the testes of the larvae of _Cacoecia cerasivorana_ and
_Euvanessa antiopa_. The number of chromosomes is large, but the
equatorial plates are diagrammatically clear. In both species 30
chromosomes are found in both first and second spermatocytes. In both,
one chromosome is larger (figs. 290 and 293, _x_). In the growth stage
(figs. 283, 284) there is a two-lobed body (or sometimes two separate
spherical bodies) which seems to correspond in size to the larger pair
of chromosomes in the first spermatocyte. In iron-haematoxylin
preparations this pair is often obscured by parts of the spireme which
are tangled around it. In safranin-gentian preparations it stains, not
like a plasmosome, but red like the heterochromosomes, while the spireme
is violet. The staining reaction at least suggests that this equal pair
of chromosomes, which may be traced through the synizesis stage (fig.
280), synapsis stage (figs. 281, 282), growth stages (figs. 283, 284),
and prophases (figs. 285-287), into the first spermatocyte spindle
(figs. 288, 290), and on to the second spermatocyte (figs. 289, 291,
292), is an equal pair of heterochromosomes comparable to the equal pair
of "idiochromosomes" found by Wilson in _Nezara_ ('05). As the various
stages are practically the same in _Euvanessa antiopa_, but somewhat
clearer in _Cacoecia_, only one figure is given for _Euvanessa_--the
equatorial plate of the first spermatocyte (fig. 293).

SUMMARY OF RESULTS.

(1) An unequal pair of heterochromosomes has been found by the author in
19 species of Coleoptera belonging to 8 families:

FAMILY. SPECIES.

I. Buprestidae Two spruce-borers, species not determined.

{ 1. _Chlaenius aestivus._
II. Carabidae { 2. _Chlaenius pe