718 THAXTER. 



type; the broad termination of the almost opaque posterior Hp-cell 

 contrasting with, and extending above and over the pale, externally 

 slightly convex anterior lip-cell: the basal cell region concolorous, 

 small, externally somewhat prominent. Spores 50 X 4 /x. Perithecia 

 85-105 X 18-22 /x. Receptacle 70-105 X 18-20 m- Appendage, 

 longer branches, 90-100 ju. Total length to tip of perithecium 175- 



225 m. 



On the wings of Sapromyza triseriata Coq. and on Sapromyza sp., 

 Nos. 1630 and 1631, Los Amates, Guatemala, (Kellerman). 



This species belongs to the section formerly separated as Ceraiomyces, 

 with which it agrees except for the presence of cell V; the receptacle 

 thus corresponding to Spegazzini's ' Labonlbeniella' . Abundant mate- 

 rial has been examined which, apart from slight differences in the 

 branches of the appendages, shows no important variation. The tip, 

 however, varies in appearance very greatly, when, as sometimes 

 happens, it is viewed laterally in the position normal to the genus. 



Laboulbenia muscariae nov. sp. 



Habit slender, the perithecium and outer appendage approximated; 

 usually straight, except that the perithecium is evenly and charac- 

 teristically curved inward from its stalk-cell to its apex. Receptacle 

 becoming faintly suffused, the basal and subbasal cells of nearly the 

 same diameter throughout, or slightly broader at the septa, becoming 

 faintly punctate: cell III-IV more distinctly punctate-striate, con- 

 spicuously rounded outward below the insertion; cell V about half as 

 long, narrow, clearly defined. Insertion-cell free, opaque, continuous 

 with the outcurved concolorous axis of the outer appendage, which 

 arises from it terminally; the basal cell of the inner appendage arising 

 laterally from its inner side, very small, hyaline, producing a usually 

 two-celled brownish antheridial branchlet on either side, terminated 

 by a pair of brownish antheridia in close contact, and lying obliquely 

 across the venter of the perithecium on either side: the axis of the 

 outer appendage consisting of usually three cells ending' in a pair of 

 branchlets; the two lower cells each bearing a branch distally on the 

 inner side, the lowest blackened externally, and bearing branchlets, 

 sometimes three side by side, of the second or even third order; the 

 branchlets distally pale, or hyaline, stout, blunt, extending somewhat 

 above the apex of the perithecium. Perithecium dark olive, the lower 

 wall-cells at first distinctly paler; the region of the subbasal wall- 



