The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1894-05-24
TROPICAL FIREFLIES.
They Furnish the Most Economical
Luminant Known.
Some Interesting Facts About These
Curious Insects.

The retirement of Prof. G. V. Riley from
the postof United States entomololist re-
moves from government employment one
of the most eminent Investigators of the
day. Science under Uncle Sans aus
pieces has done no more important work
than has been accomplished in the study
of insects. In that branch of the animal
creation Secretary Langley has made per-
haps the most picturesque research-re-
lating to the light afforded by firef1ies.
This light, Prof. Langley has discovered,
is the most econom ical iliuminant in the
world. 1t is 100 times as cheap as gas
That is to say, there is no waste, Whefe-
as the waste in burning gas or lamps IL
more than 90 per cent. In other WORDS,
the consumer pays a dollar for every
cents worth of light he gets. With cleo
tricity the waste is less, but still enor-
nous. The FREELY light expends no en-
ergy in the shap of heat.
ACOLD LIGHT WITHOUT WASTE.
If a process could be invented for pro-
ducing it in large quantities by article,
the discovery would be of enormous
benefit to mankind. Incidentally cleo
tricity and gas would be driven out of
use for illuminating purposes. That the
secret will be found sooner or later is not
at allunlikely. The notion formerly held
that the light was part and parcel of the
life of the FREELY has been exploded. 1t
Is now believed to he simply product OF
chemical com bustion.
Such being the case, it ought to be
practicable to reproduce the phenomenon
in the laboratory even on a large scale.
This peculiar light, termed "phosphores-
cence," has received little attention
from scientists up to date. 1t affords an
attractive field for investigation. The
supposition is that it is made by the
slow combustion of material secreted
under the control of the nervous system
of the insect. 1t is produced at one four
hundredth of the cost of energy expended
in candle flame. Nothing is in the
shape Of heat, the light-giving organs
having the same temperature as other
parts of the animal.
More than $50 families of animals on
land and in water, embracing tens of
thousands of species, produce such phos
phorescent light. They yield enough of
it to illuminate London, Paris and New
\ S0NttAA
with luminous curstaceans, jellyfshes,
&c.. not to mention innumerable vegeta-
BILE Organisms, each of which is tiny
lantern. In the depths swim lamp bear
ing fishes On land crawl glow worms
and "electric centipedes," while in the
air frefiies and lightning bugs" of
many kinds disport themselves. All of
this light crowded into one place would
hardly affect thermometer.
FREELY OF THE TROPICS.
The most brilliant light afforded by
any land animal is that of the famous
FREELY of the tropics known as the
"cucujo."s Thirty-eight of them yield
one candle power. Photographs have
been printed by two minute exposure of
bomide plates to their illumination.
People In Cuba confins them in paper
lanterns for going about the country at
night or for indoor lighting. Sometimes
they attach one of the insects to each
foot for travelling in the dark, to serve
as guide to the path. Also they use
them as ornaments for the dress and
hair.
1t is with these freflies that Prof.
Langley conducted his experiments
They are beetles, beginning life as grubs
Skip-jacks" or spring -tails" they are
sometimes called. because, when placed
on their backs, they jump over with a
clicking sound. A small species of the
same family is found in Florida and
Texas. They have two luminous spots
on the thorax and another on the abdo-
men. Damp evenings are most favora-
BILE to the light-gjving, the object of
which is presumably to attract the sexes
The young larvae feed largely on snails
to which their bite is poisonous. The
luminous organs are developed before
the insects leave the eggs.
Now, a theory formerly held was that
these firef1ies stored up light in the day
time for emission at night, as is done
by the so-called luminous paintn of
calcium sulphide. But it was found that
they shone as brightly as ever afterbeing
confined for ten days in darkness
Some that were carried all the way from
Cuba to Havre. in the pitch black hold
of a vessel, were brilliant on their ar
rival. A more striking disproof, how
ever, was afforded by batch Of larva
Matched in the DARK, from eggs laid in