Histological sections (hematoxylin and eosin) of Diporeia (Amphipoda) collected from Lake Superior. Notice (A) the histologically normal ovaries (large arrows) of an amphipod not displaying a microsporidian infection in the muscle tissue (small arrow) and (B) melanized hemocytic encapsulation near the ovaries (small arrow) of an amphipod displaying a microsporidian infection (Dictyocoela diporeiae n. sp.) in the muscle tissue (large arrow). Scale bar = 25 µm.