Fig. 5. Extruded LECs are removed by circulating haemocytes. (A) Macrophage-like haemocytes circulate under the pupal epidermis basal lamina extending and retracting leading lamellipodia (arrowhead). Haemocytes were visualized in vivo through the pupal cuticle by the expression of membrane-bound Src-GFP (green) using a haemocyte-specific driver (Srp-Gal4). (B) Travelling cells in the haemolymph are recruited to the basal surface of LECs. The actomyosin cytoskeleton of LECs was visualized by the expression of Sqh-GFP using confocal XZT acquisition. The apical constriction of LECs (small arrowheads) was followed by the attachment of bright fluorescent bodies to their basal side (large arrowhead). (C) The recruitment of haemocytes to the basolateral surface of LECs occurs sequentially to constriction. Simultaneous in vivo visualization of LECs and histoblasts (ubiquitous expression of Stb-YFP, red) and haemocytes (Srp-Gal4/UAS-GFP, green) (see Movie 10 in the supplementary material). Snapshots show LECs undergoing apical constriction (arrowhead) and being engulfed from their basal surface by haemocytes (asterisk) extending cytoplasmic projections (small arrowheads). Transverse z-projections show that encapsulation initiates before LEC delamination is completed and is extremely fast. The whole process (apical constriction, delamination and engulfment) takes place in approximately 45 minutes.