The two genera of Harpellales (Trichomycetes) found most frequently in Chironomidae (midge) larvae, namely Smittium in the hindgut and Stachylina in the midgut, are easily distinguished in most instances. However, cases are reported in which Smittium trichospores extrude prematurely as they pass through the midgut, with the sporangiospore attaching to the peritrophic membrane and thereby leading to very limited thailic growth that resembles an immature Stachylina thallus. This development appears to be common in Smittium longisporum and Sm. perforatum, and may occur less frequently in some other species of Smittium. Methods to identify such 'false' Stachylina thalli are discussed.
- aquatic insects