MONOGRAPH OF THE LABOULBENIACE^E. 



303 



The types of this species were found on the upper surface of the abdomen of its curious host, 

 among specimens of the latter contained in the Museum collection at Cambridge. The dozen 

 types obtained show a considerable variation in the number and position of the appendages at 

 the base of the stalk-cells of the pcrithecium. The latter appear to arise always from the same 

 cell, whether the individual produces one pcrithecium or more than one. In a single instance 

 three pcrithecia are developed, while a majority appear to have two. The few specimens acces- 

 sible of the only American Deleaster were examined carefully, in the hopes of finding a similar 

 parasite, but without success. 



CORETHROMYCES Thaxter. Plate IX, figs. 1-6. 



H 



Troc. Am. Acad. Arts and Sci. Vol. XXVII, p. 36, and XXVIII, p. 180. 



Receptacle consisting of several superposed cells, the sub-basal cell and rarely also the cell 

 above it producing a stalked pcrithecium, the terminal cells giving rise to several branched 

 appendages. Antheridial cells superposed to form an obliquely septate branchlet with projecting 

 necks. Pcrithecium symmetrical or nearly so, the stalk-cell well developed ; its cell-rows of four 

 cells each. Spores once-septate. Trichogyne filamentous, simple or branched. 



The material on which the original description of this genus is based was so insufficient that 

 it has been necessary essentially to modify the present diagnosis in the light of more abundant 

 data subsequently obtained. It approaches Rhadinomyces more closely than any other genus, 

 especially in the character of its antheridia, and may eventually have to be united with it. In 

 all three species, however, a cell is present above the sub-basal cell of the receptacle, which is 

 either sterile or produces a second perithecium, while in Rhadinomyces the secondary perithecia, 

 which are very commonly developed, arise invariably from the sub-basal cell of the receptacle. 

 There arc other differences in general habit, chax-acter of the appendages, and details of struc- 

 ture in the antheridial branchlets, which, though of less importance, all tend to make it seem 

 advisable to keep these genera distinct until further data concerning them can be obtained. 



In development the spore first divides into five superposed cells. The terminal one by suc- 

 cessive proliferation from one side, produces a tuft of terminal branches and branchlets, which 

 are often broken or obsolete in older individuals. The sub-basal cell produces a single perithe- 

 cium, which first appears as a triangular cell cut off from its anterior upper portion, as in 

 Laboulbenia. The cell above this either remains unchanged or produces a second perithecium, 

 while the sub-terminal cell gives rise to the main appendages. The antheridia arise as branch- 

 lets from the main appendages, the terminal cells of which are sterile. The trichogyne is well 

 developed, slender, septate, and more or less branched. 



The three species are found on beetles belonging to the Staphylinidia?, and inhabiting very 

 wet situations, especially along the margins of streams or ponds. 



Corethromyces Cryptobti Thaxter. Plate VII, figs. 1-2. 



Proc. Am. Acad. Arts and Sci. Vol. XXVII, p. 36, and XXVIII, p. 181. 



Perithecium usually very long and slender, becoming uniformly suffused with brown ; 

 straight, slightly inflated toward its base, tapering very gradually to its blunt symmetrical apex ; 



