Sessile hemocytes are phagocytic and are distributed throughout the mosquito body. (A-B) Bright field and fluorescence overlay of sessile hemocytes in the dorsal abdomen of two-day-old mosquitoes at 24 hours post-infection with E. coli (red, CM-DiI stained hemocytes; green, GFP-E. coli; blue, Hoechst 33342 stained nuclei). Hemocytes are distributed throughout the body wall and melanization products have been internalized by the pericardial cells that flank the heart. Yellow horizontal dotted lines outline the heart, asterisks mark the location of ostia, and white vertical dotted lines mark the abdominal sutures. (C-D) DIC and fluorescence overlay of sessile hemocytes in the dorsal abdomen of 16-day-old mosquitoes at 24 hours post-infection with E. coli. Hemocytes are aggregated in the periostial regions. (E-G) Bright field and fluorescence overlays of sessile hemocytes in the ventral abdomen of two-day-old (E-F) and sixteen-day-old (G) mosquitoes at 24 hours post-infection with E. coli. Diamonds mark the location of the abdominal ganglia. (H-J) Bright field and fluorescence overlays of sessile hemocytes adhered to the abdominal wall and the tracheae in the abdominal pleuron (Terg, tergite; Pl, pleurite). (K-M) Bright field and fluorescence overlays of sessile hemocytes in the thoracic indirect flight muscles. The box in panel L is magnified in panel M, and shows hemocytes as well as rows of densely packed myocyte nuclei. (N-R) Overlays of hemocytes in the head (N; Sc, scape), maxillary palps (O), legs (P), and wings (Q-R). (S-T) Overlays of hemocytes bound to the midgut (S) and Malpighian tubules (T). Unless otherwise stated, samples shown are from six-day-old adults at 24 hours post-infection with E. coli. Orientation guides and scale bars apply to the image they appear in and each subsequent image, until new guides are presented. A, anterior; P, posterior; D, dorsal; V, ventral; L, lateral; Pr, proximal; Dt, distal.