Ultrastructure of the Wolbachia strain wMelPop in apoptotic cystocytes in region 2a/2b of the germarium. A, B, Wolbachia accumulations in apoptotic cyst cells, low magnification view. C,D, bacteria framed in panels A, B depicted at higher magnification. Bacteria showing normal morphology (arrows), bacteria with matrix of low electron density (white arrowheads), bacteria with matrix of low electron density and disrupted cell wall (black arrowheads) in the cytoplasm of dying cysts. Scale bars: 2 μm.