Key to described Nealyda species in the United States based on female genitalia

1. Signum consisting of a large, visible spine and faint lines of dissociated granules extended laterad and posteriad of the spine................................................................. 2

— Spine of signum small; signum dominated by oval, continuously sclerotized granular lateral areas.......................................................................... N. pisoniae Busck

2(1). Signum a curved spine.................................................................... 3

— Signum a straight spine................................................................... 4

3(2). Ductus bursae with broad swollen area halfway; papillae anales slightly rectangular.. N. bifidella Dietz

— Ductus bursae evenly membranous, without swollen area; papillae anales elliptical..................................................................... N. grandipinella Bennett and Hayden

4(2). Papillae anales fused basally, nearly the size of corpus bursae................. N. phytolaccae Clarke

— Papillae anales separate, smaller than corpus bursae.......................... N. kinzelella Busck