Figure 5 in Evolution of cheaper workers in ants: comparative study of exoskeleton thickness

Figure 5. Cross-sections through prothorax of smallest worker (head width 0.56 mm) of Dorylus orientalis (A) and of larger conspecific workers (B – E) with indication of head width (HW). Note increase of cuticle thickness with increasing worker size. All photographs at same magnification (oe: oesophagus, lg: labial gland, mf: muscle fibres, ptg: prothoracic ganglion).