MUSEUM NOTES. 
97 
by those specially interested in natural history, are 
nevertheless widely distributed, especially in the tropics, 
and are far more varied and abundant than is generally 
supposed. 
Of the many provisions which nature has developed 
for the destruction of its surplus insect population, there 
are few more effective in restraining the undue increase 
of many forms than these fungus diseases which, in 
some instances, may afford the most effective means 
of destroying noxious species. Among these fungus 
parasites there are several different classes which do 
their work in different ways, some of them as destructive 
as the plagues which ravage higher animals and often 
more acutely epidemic; while others, even more peculiar 
from a scientific standpoint, depend for their existence 
on the continued life of their host-insects, exerting no 
destructive influence. 
Among destructive forms the Entomophthorae or 
“ Fly fungi,” which take their vulgar name from a 
disease of the house fly, common all over the world, 
are responsible for widespread epidemics among various 
insects: flies, grasshoppers, caterpillars, plant-lice and 
many others, the contagion being scattered in this 
instance by means of “ spores ” which are shot off from 
their filaments by a special mechanism with great 
force and in countless numbers ; a single spore bearing 
certain death to any proper host which it may touch. 
If therefore a disease of this nature is once started 
in a region where its proper victims are present in 
great numbers it may, if the weather conditions are 
favorable for its development, bring about an almost 
total destruction of its hosts over wide areas. The 
economic importance of such diseases has been more 
fully recognized in recent years and one of the 
Entomophthora diseases has been used artificially and 
with success in the United States for the last three 
seasons in an attempt to control the widespread 
destruction wrought by the caterpillars of the Brown-tail 
Moth, which, since its importation on nursery stock 
from Europe a few years ago, has increased to such 
an extent that it has devastated the forests in many 
parts of New England. 
Fungus diseases of this group, however, do not 
appear to have been largely developed in the tropics 
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