Anamorph on the host insect: several white to yellow synnemata arise from all parts of the insect body. Synnemata usually 5-12 mm long, sometimes up to 30 mm in length, with a white cylindrical to clavate, powdery head and sometimes a sterile white to yellow stipe, sometimes irregularly branched. The conidiogenous structures are mostly more compact and swollen than in pure culture, the conidiogenous cells forming in complex clusters, the basal part 2.5-3 (-3.5) µm in length and 2.5-3 µm diam. and almost globose, with a distinct cylindrical to narrowly conical neck 2-3 µm in length and ca 0.5 µm diam., proliferating percurrently. Conidia 3-3.5 x ca 2 µm, ellipsoidal to fusiform-ellipsoidal, aseptate, hyaline, thin-walled, smooth, without an epispore or gelatinous sheath. Anamorph in culture: colonies on malt-agar growing moderately fast, consisting of a basal felt from which numerous conidiophores arise. Fresh isolates are powdery and sometimes with conspicuous yellow synnemata; older strains with floccose aerial mycelium, at first white, remaining so or turning bright yellow or cream. Reverse cream to yellow, in fresh isolates often brightly yellow. Odour indistinct. Vegetative hyphae smooth-walled, hyaline or containing yellow granules. Conidiophores mainly arising from the submerged mycelium, usually measuring 100-300 x 1.0-2.5 µm, in some strains with a floccose overgrowth arising as sidebranches from aerial hyphae. Conidiogenous structures smooth-walled, hyaline, consisting of verticillate branches with whorls of 2 to 4 conidiogenous cells. Conidiogenous cells 5-15 x 1.2-2.5 µm, with a swollen basal portion tapering into a distinct neck about 0.5 µm diam., proliferating percurrently. Conidia 2-3.5 x 1-2 µm, ellipsoidal to fusiform, sometimes lemon-shaped, smooth-walled, hyaline. Chlamydospores absent. Teleomorph: not definitely known; links have been made with several teleomorph taxa, but no clear connection has been made with the anamorph as currently circumscribed.