_Sanford, Fla., March 11, 1885._
_EXCHANGES._
LIMITATION OF THE VISUAL FIELD OF THE WORKER HONEY-BEE’S OCELLI. BY THE
REV. J. L. ZABRISKIE.[9]--The honey-bee is a remarkably hairy insect. On
the head the hairs are dense, and of various lengths; and they cover
every part, even the compound eyes and the mandibles. The antennæ,
however, are apparently smooth, having only microscopic hairs; and a
path through the long hairs, from each ocellus, or simple eye, directly
outward,--to be described more fully presently,--is practically smooth.
The ocelli are so situated that when the bee is at rest and the face
vertical, they are directly on the top of the head, arranged as an
equilateral triangle, and one ocellus is directed to the front, one to
the right side, and one to the left[10].
Long, branching hairs on the crown of the head stand thick like a
miniature forest, so that an ocellus is scarcely discernible except from
a particular point of view; and then the observer remarks an opening
through the hairs--a cleared pathway, as it were, in such a forest--and
notes that the ocellus, looking like a glittering globe half immersed in
the substance of the head, lies at the inner end of the path. The
opening connected with the front ocellus expands forward from it like a
funnel, with an angle of about fifteen degrees. The side ocelli have
paths more narrow, but opening more vertically; so that the two together
command a field which, though hedged in anteriorly and posteriorly,
embraces, in a plane transverse, of course, to the axis of the insect’s
body, an arc of nearly one hundred and eighty degrees.
These paths through the hairs appear to me to be indications that the
ocelli are intended for distant vision, although the opinion that near
vision is their function is held by eminent opticians.
The ocelli are nearly hemispherical, and the diameter of each is about
fifteen times that of a facet of the compound eye. Such a form of lens
would, I will concede, indicate for these organs a short focus, and
hence, a fitness for near vision.
But if the ocelli are intended for near objects, it is difficult to
understand why they are surrounded by a growth of hair so dense as to
permit unobstructed vision only in a very narrow field, and why they are
so placed on the top of the head as to be debarred from seeing any
objects in the neighborhood of the mandibles and the proboscis, the
ability to see which objects would appear to be very necessary in the
constant and delicate labors of the worker honey-bee among the flowers.
Dr. Zabriskie exhibited the head of the worker honey-bee for the
purpose of illustrating the above remarks. At the conclusion of his
observations, he added: “Besides the worker honey-bee, I have brought
for exhibition the drone and the queen of the same species, and the
queen-cells; the queen of _Bombus Virginicus_, one of our native
humble-bees; the _Melissodes binotata_, male and female; the _Melissodes
pruinosa_, both sexes; the beautiful _Anthophora dispar_, male and
female of Tunis, Africa; and the celebrated little stingless bee of
Abyssinia, the _Trigona Beccarii_, which lives in immense colonies, and
stores large quantities of honey. The _Anthophora dispar_ has a very
long proboscis. The possession of such a proboscis by our own bees would
add millions of dollars annually to the wealth of the United States.”
_CANADIAN DEPARTMENT._