, 1897-04-27
ARGUS %OUTPO1NTED.
AN INSECT THAT is CREDITED WITH
THlRTY-SIx THOUSAND EYES.
scientists Have Made Some Wonderful Dis.
coveries In This Line. bnt They Give the
Palm to the Common Dragon Fly-Ir-
teresting Natural History.

coveries In This Line. but They Give the
Palm to the Common Dragon Fly-Ir-
teresting Natural History.
Thirty-six Thousand eyes in one head
This may appear a little like exaggera-
ton, but it is fact. Science, backed by
the microscope, says so, and science
never stretches the truth. Should it do
30 it would cease to be a science.
Argus was tabled to have "a hundred
eyes, but Argus would be a very insig-
nificant curiosity compared with the
latest discovery in the insect kingdom.
There are numbers of insects with 100
and even 0 eyes, but when the num-
Der of optics allotted to q single insect
reaches up into the thousands the IDEA
is startling.
Naturalists have recently been engag-
cd in the study Of this most interesting
subject. Each succeeding day brings
more marvellous results until the as
founding discovery has been made that
the common dragon fly, or mosquito
hawk, while seemingly possessed of
only two visual organs, really has as
many as Sc, goo, each of the two visible
to the ordinary observer being subdivid-
ed into IS, 900 separate lenses, each eye
let having Il distinct nerve connecting
it with the brain and acting entirely
independently of its myriads of com.
panions.
The theory most generally adopted
by scientists is that, while far superior
to the eye of higher animal life us re-
CARDS moving objects, the power of ob-
servation of the composite eye is inferior
in its application to stationary things.
The reason is this: The moving object
is first observed by one of the thousands
of facets, which perceives it for the in
finitesimal part of u second that it takes
to get out of the arc of vision of that
particular lens and pass into that of IL
other, each movement being separately
telegraphed to the brain by the facet on
duty. But with a stationary object it is
different, since for some reason the
minor organ fails to focus accurately,
and SO render the object less distinct
than when viewed by eyes of only one
lens each.
A question which continues to puzzle
the scientists is whether the animal or
insect sees as many images of the objects
as he has eyes. or facets. For instance,
does the dragon fly fancy he is fitting
over SO, 900 ponds, or does he see only
one? Probably one, for tho two eyes OF
a human being in normal condition show
but a single image. Besides, apart from
the lenses and cones i'll front, the eye is
a hollow sphere pierced by perforations
running down the facets toward the
center. 1t follows that the light impress.
sions thus form IA single picture, or mo-
sale, as it were, each facet presenting u
slightly different picture from its neigh
Dor and the group presenting IL perfect
whole.
There are many other animals pos.
sessed of an extraordinary number of
eyes,. James Francis Stevens, a noted
entomologist, is said to have recorded
1000 such species in his garden in one
afternoon, while Francis Pascoe, anoth-
er noted naturalist, counted so different
specimens on his library window.
The common scallop,' for instance, has
many eyes scattered irregularly over its
body. The lobster has massed together
in each orb more than u hundred dis
tinct eyes, and, unlike human eyes,
these are set forward, instead Of being
sunk inward. Does the poor lobster see
things Il hundredfold? If so, possibly it
is in avoiding the 80 imaginary lobster
pots that he stumbles into the real one.
The common house fly has 1000 eyes,
the cabbage butterfly II, 900, the drone
fly s. 900, the h%oneybee 6, 800. But still
at the head of the list stands the mos.
quito hawk, or dragon fly, with his
SO, 900. AS his name suggests, while
not despising any of the smaller insects,
his specially is the mosquito. Indeed he
has SO succeeded in terrorizing these lit.
tie pests that his lifeless form still fills
them with alarm. In localities where
mosquitocs are troublesome an cffectuaI
mode of Kidding the place of them con,
sists in suspending a dead dragon fly
from the ceiling by u piece of thread.
Those who have tried it say that it has
never been known to fail.
+ Up to a certain point these multi
tudinous eyes may be compared to win.
dows fitted with innumerable panes Of
glass. The pnnes, however, are of diff
ferent forms. Some, like those Of the
bee and the ant, are six sided, remind.
ing us of tho pattern so common in
Gothic architecture. Some, again, arc
diamond shaped and others square.
Another interesting branch of this in,
teresting subject is the study of the near
and far sighted insects. Johanna Null
Ter long ago pointed out that the flight
of insects depends upon their power of
vision. This will account for the differ
ence in the flights of the common house
fly and the wasp. The IL confines him
self to short flights. AS his food is al
ways to no found within u small area,
he flies in short curves and circles. But
the wasp is remarkably sharp sighted,
and the arrangement of the lenses shows
that his line of vision is decidedly for
ward. Here, again, the dragon fly is pre-
eminent. He has well been called the
tyrant Of the air. He alone is able to
take perfectly straight lines ut enormous
speed for long distances, evidently see
ing we'll what is ahead of him.-New
Orleans Times-D Democrat.