MONOGRAPH OF THE LABOULBENIACEiE. 



Presented May 8, 18'Ji>. 



PART I. 



In the first part of this Memoir I have given an account of the History, Distribu- 

 tion, General Morphology and Development, Hosts, etc., of the LaboulbeniaceaB ; while 

 the second part comprises a systematic examination of the species and genera illus- 

 trating the family. Before entering, however, on the detailed consideration of the 

 topics mentioned, it has seemed desirable, by way of introduction, to present a brief 

 account of the more general characters of these plants. 



Unlike the majority of fungi which subsist as parasites of living insects, the 

 present group includes none of the conspicuous productions that are so characteristic 

 among entomogenous fungi generally; and their usually minute size doubtless 

 accounts, in some degree, for the fact that, although they are in certain respects 

 among the most important of fungus organisms, they have been so long neglected by 

 botanists and so generally overlooked or disregarded by entomologists. When ex- 

 amined in situ on the host insect, they appear in general like minute, usually dark- 

 colored or yellowish bristles or bushy hairs, projecting from its chitinous integument 

 either singly or in pairs, more commonly scattered, but often densely crowded over 

 certain areas on which they form a furry coating. Unlike other entomogenous fungi 

 also, the Laboulbeniacese can lay no claim to economic importance ; and although 

 they may be said to produce a contagious cutaneous disease, they give rise to none 

 of the fatal epidemics which are liable to be associated with the parasitism of species 

 of Cordyceps and Entomophthora. On the contrary, the very existence of these 

 parasites would seem to be dependent on the fact that the host is not destroyed by 

 their attack ; since their own life ends with that of the insect to which they are 

 attached, and their perpetuation from generation to generation and from year to year 

 is undoubtedly dependent on the direct transference from one living insect to another 

 of their reproductive bodies. So far, then, as they are at present known, they inflict 



