A group of sensory pits is situated at the top of each of the forewing pads near their inner angles (Figs 4, 7, 8). In nymphal I. coleoptratus (certainly in L2-L5 instars) these are large, clearly annulated and typically number ten; they are somewhat dispersed and are only occasionally contiguous. In nymphal I. muscaeformis seen these pits are smaller, less broadly annulated, typically number seven and tend to be contiguous.

The variegated, broadly and clearly darkly annulated leg members are also believed to be characteristic of I. muscaeformis at all growth stages (Thomas, 2006).