The Animal Parasites of Man by Fantham, Braun, Stephens, and Theobald

1. Third joint of antennæ fringed with fine hair

on anterior and posterior margins; fringe on anterior margin conspicuous under a hand lens magnifying 15 diameters (nominal) when head is viewed in profile 2. Third joint of antennæ with fringe of fine hair on anterior margin so short as to be scarcely noticeable under a hand lens magni- fying 15 diameters (nominal) when head is viewed in profile (longest hairs in fringe in length not exceeding one-sixth of width of third joint); palpi long and slender 3.