INTRODUCTORY NOTE. 



In the fourth volume of the " Memoirs of 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 Entomophthoreas, with notes on all the species then known, which 

 was intended to form the first of a series designed to include all the American funo-i 

 parasitic on insects. The subject was suggested to me by Professor Farlow, while I 

 was a student in his laboratory, as one promising data of sufficient interest to furnish 

 material for a doctor's thesis. The Entomophthoreae, however, having proved ade- 

 quate in themselves to fulfil this requirement, the remaining entomogenous forms 

 were laid aside in the hope that, at some future time, the original plan of a complete 

 monograph 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 

 family of Entoraophthorese, several groups were in a general way distinguished. Of 

 these one comprises the entophytic and probably commensalist Schizomycetes (?) rep- 

 resented by the genus Enterobrus 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 

 second includes the perfect and imperfect or" isarial" conditions of the entomogenous 

 species of the genus Cordyceps and its allies ; while a third embraces all the members 

 of the then small and little known family of Laboulbeniaceae. To these should be 

 added a few miscellaneous forms parasitic on insects ; and perhaps, also, such fungi as 

 are found in nature only on the remains or excreta of certain insects. The last, how- 

 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 single paper. In view of this fact, the Laboulbeniaceaa 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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