Pathology of a Gammabaculovirus in Its Natural Balsam Fir Sawfly (Neodiprion abietis) Host

Figure 5

Cross-section of a healthy larval midgut. Epithelial cells are elongated and abutted against circular (CM) and longitudinal (LM) muscles; tracheole epithelial cells (TE) are also present. The nucleus (N) is elongated and centrally located in the cell. Heterochromatin (Hc) and invaginations of the nuclear envelope (arrowhead) are evident. Three successive stages of what appears to be a secretory process from these cells (a, b, and c) are apparent. Epoxy section, photomicrograph. Scale bar = 20 μm.