The Fine Structure of Mosquito Midgut Muscle

The midguts and associated muscle fibers of A. quadrimaculatus were dissected out in saline solution and immediately fixed in a solution of 1 % osmium tetroxide in 0.1 M potassium phosphate buffer, pH 7.2, for 5 min at room temperature. The specimens were subsequently dehydrated in ethyl alcohol for 2 hr and embedded in Epon 812 (Luft, 1961). Sections were cut on an LKB ultra microtome with glass knivesAfter mounting on Formvar film, we stained the sections with uranyl acetate (Watson, 1958) and/or with lead hydroxide (Millonig, 1961). Subsequent to the staining, the sections were covered with carbon. Micrographs were taken with a Siemens Elmiskop I.