D. coelobrocha was found developing in a maizemeal-agar plate culture that had been planted with partly decayed leaves of Fagus grandifolia collected near Webster, New York. It subsists through capture of free-living nematodes[long dash]e.g., Plectus parvus, Rhabditis spp., Wilsonema sp.[long dash]in 3-celled constricting rings attached at intervals to its mycelial hyphae by stout 2-celled stalks. These rings, though resembling the constricting rings of the 6 related nematode-strangling hyphomycetes previously described, operate in a distinctive manner; for, whereas in the other forms the eel worm is gripped between all 3 arcuate segments composing the ring, in the present species it is most often gripped only by the proximal and median segments. After closure of the ring the swollen parts of the 2 segments are broadly indented into the animal''s body, but the slender cord-like connection between the segments is deeply indented into the body and thereby serves most effectively in bringing about strangulation. The pull required to draw the cord-like connection into its deeply indented position is partly provided by the contraction of the distal arcuate segment, which thus contributes power to the strangulating action even though usually lacking contact with the animal. The conidia of the fungus, produced singly on tall erect conidiophores, are broadly fusiform, and ventri-cose. They are usually partitioned by 4 cross-walls in such wise that the distended barrel-shaped median cell is much larger than the 2 cells above it and the 2 cells below it; while, further, the discoid parabasal and penultimate cells are markedly shorter than the basal and apical cells.