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from the bottom of this issues a canal, which becomes narrower towards the inner
opening, and which during the course inwards is about rectangularly bent. The
canal is comparatively long, not going the shortest way through the chorion, but
running somewhat tangentially in the same. That form of the micropyle quite agrees
with the one in Gerris lacustris, described and figured by Leuckart (Muller: Arch. f.
Anat. Physiol. und Wissenschaftl. Med. 1855, 158, Taf VIII, fig. 26) as well as the
Halobates-egg upon the whole shows great accordance with the Gerris-egg.
In colour the eggs vary from yellowish white to red or reddish brown; it is,
however, not the eggs of the different species that have a different colour, but the
eggs of the single species run through the scale. The fact is that the colour is
chiefly dependent on the contents, as the chorion is transparent, and only slightly
yellowish; the eggs in which the development has not begun are yellowish white,
and gradually as the embryo is developed, the egg grows darker and becomes at
last red or reddish brown. The eggs mentioned by Witlaczil (l. c.) are also called
brick coloured, and they had fully developed embryos. In the eggs with a very
thick chorion this can be a little more yellow than in the thin shelled ones.
From the above list of the material it is evident that the Halobates-species
deposit their eggs on floating objects of the most different sorts. It is, however, worth
remarking that they almost always are of animal or vegetable origin, of course,
because such objects most frequently are present. The material contains only two
exceptions herefrom, No. 5 and 9, in the former case the eggs are laid on a cork
stopper, and in the latter on a small coal-slag. The number of the eggs varies from
about 30 to many thousands. It seems as if the females also can lay their eggs
without their being fixed to any object. The specimen No. 6 is a longish, nearly
band-shaped mass of eggs glued together; only some quite thin threads are to be
seen in it, which probably form the original substratum for the eggs, but that
object is so extremely small, that it cannot have been of any importance for the
floating power of the eggs ; it must only have been the floating power of the eggs
themselves that in this case has supported them. As it seems to be rare for the
eggs to be laid in that manner, it probably only happens when the females have found
no floating objects. As mentioned before females in some cases have been found
bearing 1 — 3 eggs at the end of the abdomen; it may be supposed, I think, that the
females bear them only for a short time, till they find a suitable place for
deposition; if such a one is not found, they may thus possibly also lay them without it.
The deposited eggs are attached with a glue-like substance which in my
specimens is more or less abundant, but it is always distinctly present, and the eggs
are solidly fastened. Most frequently the glue-like mass is abundant and surrounds
the eggs entirely, and when an egg is isolated, it is seen to be more or less
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