Some observations on altered morphology in Amphipsyche meridiana (Hydropsychidae: Trichoptera) larvae from the Pasak Jolasit Dam Outlet, central Thailand

Amphipsyche meridiana Ulmer, 1909. larvae from the River Pasak below the Pasak Jolasit Dam were examined for alteration of morphological structure such as the anal papillae, surface, and tracheal gills of the larvae. The tracheal gills were the most altered followed by surface and anal papillae. Factors such as conductivity, and inputs of orthophosphate, sulfate, turbidity, other contaminants, and/or stream profiles may have contributed to the abnormalities.