52 
INSECTS AN FUNGUS HOSTS. 
In addition to such enemies as that mentioned, caterpillars 
and indeed other insects as well — have to contend with a mucb 
more potent agent in accomplishing their destruction. You will 
remember that one of the finest rural industries of France was 
ruined for some years by reason of a malady that decimated 
the caterpillars yielding the silk of commerce, and how% after 
five consecutive years of laborious investigation, the renowned 
Pasteur arrived at the knowledge of a practical means for check- 
ing the evil and preventing its occurrence in the future. On 
reference to his “Etudes sur la Maladie des Vers k Soie,” you 
will find that this destruction of the silkworms of the south of 
France was occasioned especially by two diseases, “ la pebrine" 
and “ la fiacherie,” the one determined by the presence of a 
psorosperm and the other by that of a schi:5omycete or bacterium 
—both low forms of fungi, and giving rise to these two special 
diseases, which are hereditary as well as communicable, 
bimilarly at an earlier date another silkworm disease, “ I’efflores- 
cence,” had been shown by Davaine and Robin to be due to au 
entomogenous fungus named then— by Balsam — Botrvtis 
Eassiana, and afteiwards Isaria destructor. 
Silkworms are not the only caterpillars thus affected 
nor are the latter and insects generally subject to funru' 
diseases only, when reared under artilicial condition; 
This last mentioned fungus, Isaria destructor, was earl 
found o be coimnunicable and to occasion disease i 
insects belonging to quite different genera aurl « i 
than does the silkworm, and afterxlvi \ ^ 
whilst living in the open even under natural i 
caterpillars and almost all other insects 
liable to disease due to the gi-owth of nar r ^ 
them. To such an extent S tTiis so 
have been written dealim^ with fnn ’■ ’ memoir 
such, for example, as N. G^avV- ? r 
known to form the bases of Punfrn^rl Insects that ar 
tomopthoreie of the United States ” Tbaxter’s “ Eii 
Insectorum Morbis qui I'-i'^^silstschik’s “ R 
work publish^ oij" b 1.. 
Society of New Russia. ^ of tlie Naturalists 
