Fig. 3
From: The loss of flight in ant workers enabled an evolutionary redesign of the thorax for ground labour
Tension muscles (red) connect head, furcae, and petiole along the thorax in ant workers (Euponera sikorae). Furcae (blue) are skeletal structures that relay force/stress inside the thorax. A direct muscle (Idlm1) originates dorsally at anterior edge of the mesonotum and pulls the head up. External trochanter muscles (orange, right legs only). Posteriorly, muscles arising on metafurca insert on the anterior end of the petiole, pulling the abdomen to maintain horizontality. T1, prothorax. T2, mesothorax. F1, profurca. F2, mesofurca. F3, metafurca. Cx1, Cx2 and Cx3 are coxae (= first segments) of the fore-, mid- and hindlegs respectively