Fig. 5.

Ventral view of the trunk. The inner, pharyngeal openings to the spiracles (s) of B. stygius (a) and of B. mcnutti sp. nov. (b) are approximately equal in diameter to their outer openings. The spiracles of B. mcnutti (b: 1, 2) are about half the diameter of the pharynx at their midpoint (4). The slightly cupped spiracles of B. stygius (a: 1, 2) are more dorsoventrally flattened and in widest diameter approximate the diameter of the pharynx (4). Observed ventrally, the endostyle (e) of B. mcnutti appears more elongate than that of B. stygius. The rectum (r) voids slightly left of the mid-line in each species