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NATCTKAL HISTORY. 
fully provided by Providence w^ith a felf-pof- 
fefllng ray, in the fun’s abfence, to fliew its 
mate the fpot where it is anxioufly waiting 
its company. Thus are the banks and hedg- 
es adorned with their little illuminations, 
while the nightly traveller is charmed witk 
their beauteous fplendor. 
Their luminous power depends on a liquor 
placed at the lower extremity of the infeft, 
which by fusion renders it more fliining, or 
by dilating or contracting itfelf withdraws 
or emits it at pleafure. That the light is 
caufed by a fpecies of phofphorus, is evident, 
from the animal, when ci'ullied, leaving up- 
on the hand a luminous matter, which conti- 
nues itsluftre until it isdried. 
The perfect infeCt flies in autumn even- 
ings, and frequents plantations of juniper- 
trees. 
The F I R E - F L Y of ike Eafi- Indies.. 
^ i ^ HIS fly is about an inch long, and an inch- 
broad. Their head is brown, and has two- 
fmall horns, or feelers. They have four 
wings. On their backs, they have a black 
bag, containing a luminous liibllance, which 
is concealed by their wings, unlefs. expanded 
during tlieir flight. In rainy fcalbns,, they 
fwann among; trees, and feect npon their 
bLolToiivt. Of thefe flies„ there are feveraf 
i'pecici 
