Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1897-05-13
ARGUS OUTPOINTED.
AN INSECT THAT IS CREDITED WITH
THIRTY-Slx THOUSAND EYES.

Scientists Have Made Some wonderr ulD Dis
eoveries In This Line. bat They Give the
Palm TO the Common Dragon F1y-In-
teresting Natural History.
Thirty-six thousand eyes in one head!
This may appear a little like exaggera-
tion, bus it is fact. Science, backed BY
the microscope, says so, and science
never stretches the truth. Should it do
so it would cease to be science.
Argus was tabled TO have hundred
eyes, but Argus would be q very insiy-
nificant curiosity compared with the
latest discovery in the insect kingdom.
There are numbers Of insects with 100
and even 800 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 80, 600, each Of the two visible
to the ordinary observer being subdiyid-
cd into $4,000 separate lenses, each eye
let having q distinct nerve connecting
1t 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 ms re-
CARDS moving objects, the power of OBJ
servation Of the composite eye is inferior
in its application to stationary things.
The reason il this: Tho moving object
is first observed by one Of the thousands
OF facets, which pcrcoives it for the in
fnitesimal part Of second that it takes
to get out Of tho arc of vision Of that
particular lens and pass into that Of an
other, each movement being separately
telegraphed to the brain by the facet ON
duty. But with 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 80, 600 ponds, or does he see only
one? Probably one, for the two eyes Of
ahuman being in normal condition show
but single image. Besides, apart from
the lenses and cones in front, the eye is
hollow sphere pierced by perforations
running down the facets toward the
center 1t follows that the light impress
sions thus form n single picture, or mo-
sale, as it were, each facet presenting o
slightly different picture from its neigh
Dor and the group presenting q perfect
whole
There are many other animals pos
sessed Of an extraordinary number Of
eyes. James Francis Stevens. noted
entoinologist, 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 irrcgularly over its
body. The lobster has massed together
in each orb more than q hundred dis
tinct eyes, and, unlike human eyes,
these are set forward, instead Of being
sunk inward. Docs the poor lobster SEQ
things a hundrodfold? II SO, possibly it
is in avoiding the 90 imaginary lobster
pots that he stumbles into the real one.
Tho common house fly has 1000 eyes,
the cabbage butterfly 1900, the drone
fly 5000. the honeybce $500. But still
ut tho head of the list stands the mos
quito hawk, or dragon fly, with his
36, 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
mosquitoes are troublesome an effectual
mode Of Kidding the place Of them con-
sists in suspending a dead dragon fly
from tho ceiling by a piece Of thread.
Those who have tried it say that it has
never been known TO fail
Up to certain point these multi
tudinous eyes may be compared to win
dows fitted with innumerable panes Of
glass. Tho panes, however, are Of diff
ferent forms. Some, like those Of the
bee ard the ant, are six sided, remind
ing rs of tho pattern so common in
Gothic' architecture. Some, again, are
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 one confines him
self TO short flights. As his food is nj.
ways TO DO found within q small area,
he flies in short curves and circles. But
tho 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 at enormous
speed for long distances, evidently see.