Key to the known pupae of Hexatoma of USA

1. Respiratory horns strongly bent toward each other, their apices swollen and rounded (Alexander 1920: fig. 297)..................................................................... Hexatoma (Eriocera) albitarsis (Osten Sacken, 1869)

- Respiratory horns slightly divergent (Figs. 9, 18)............................................................. 2

2. Respiratory horns with apex narrowed to spine (Fig. 8)........................................................ 3

- Respiratory horns with rounded apex (Fig. 17)............................................................... 4

3. Respiratory horns bent anteriorly (Alexander 1920: fig. 280).......... Hexatoma (Eriocera) spinosa (Osten Sacken, 1860)

- Respiratory horns slightly bent posteriorly (Fig. 8)................ Hexatoma (Eriocera) californica (Osten Sacken, 1877)

4. Cephalic crest consists of two pairs of horns (Fig. 17). Sheaths of antenna short in both sexes.......................... 5

- Cephalic crest consists of one pair of horns (as in Fig. 59). Sheaths of antenna elongated in males and short in females...... 6

5. Pupa generally dark brown, wing pad light yellow................... Hexatoma (Eriocera) fultonensis (Alexander, 1912)

- Pupa yellowish brown, wing pad dark brown..................... Hexatoma (Eriocera) fuliginosa (Osten Sacken, 1860)

6. Dorsum of thorax bears prominent tubercle (Alexander 1920: fig. 277)...... Hexatoma (Eriocera) longicornis (Walker, 1848)

- Dorsum of thorax smooth................................................................................ 7

7. Scape of antenna bears single prominent spine (Alexander 1920: fig. 247).................................................................................................. Hexatoma (Hexatoma) megacera (Osten Sacken, 1859)

- Scape of antenna bears two blunt tubercles (Alexander 1920: fig. 256)...... Hexatoma (Eriocera) cinerea (Alexander, 1912)