H > 
INTEODUCTORY NOTE. 
In the fourth volume of the " Memoirs o^ the Boston Society of Natural History " 
(No. VI, April, 1888), the writer published an account of the American forms belong- 
ing* to the family of Entomophthorece, with notes on nil the species then known, wliich 
was intended to form the first of a series designed to include all tlic American funiri 
parasitic on insects. The subject was suggested to me by Professor Farlow, wliile I 
was a student in his laboratory, as one promising data of sufficient interest to furnish 
material for a doctor's thesis. The Entomophthoreoc, however, having proved ade- 
quate in themselves to fulfil this requirement, the remaining entomogenous forma 
were laid aside in the hope that, at some future time, the original plan of a complete 
monoo-raph might be carried out. In the paper just mentioned, a brief summary was 
given of all the fungi characterized by this peculiar parasitism ; and, in addition to the 
fiimily of Entomophthorece, several groups were in a general way distinguished. Of 
these one comprises the entophytic and probably coramensalist Schizomycetes (?) rep- 
resented by the genus Enterobrns and its allies, to which might be added certain lower 
forms of the same order supposed to give rise to contagious diseases among insects ; a 
ond includes the perfect and imperfect or" isarial" conditions of 
o 
species of the genus Cordyceps and its allies ; while a third embraces all tlie members 
of the then small and little known family of LaboulbeniaceiB. To these should be 
added a few miscellaneous forms parasitic on insects; and perhaps, also, such fungi as 
found in nature only on the remains or excreta of 
The 
V 
ever, since they are saprophytic, cannot be called entomogenous in the more strict 
sense of the term. 
Since the completion of the monograph above mentioned, I have accumulated mate- 
rial of entomogenous fungi whenever the opportunity has offered, but have found the 
number of forms so unexpectedly large that, as in the former instance, it has become 
necessary to abandon my plan of completing a monograph of all the remaining groups 
in a sino-le paper. In view of this fact, the LaboulbeniacejB have been selected as the 
subject°of the present memoir, since they include by far the greater portion of the 
material referred to. 
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