male may undulate his tail from side to side in a slow and exaggerated manner, and the female moves her head from side to side, alternately from the male's tail. This tail-straddling walk may last for over an hour, at which point the male deposits a spermatophore, leading the female to walk over it, at which time she may either accept or reject the male's sperm. The spermatophore of this species is described as conical, 2.5 mm in height and with a colorless stalk that tapers towards the tip. This species exhibits sexual dimorphism in the shape of the premaxillary teeth. The teeth of breeding males are unicuspid and elongated when compared to the shorter bicuspid teeth of the females. These enlarged teeth are used to help abrade the female's skin and introduce the secretions on the males mental gland, found on the chin, into her circulatory system, which stimulates her to mate. Prior to egg laying, the female searches for a suitable oviposition site in the stream. Nest sites are frequently under rocks, sometimes logs, and perhaps vegetation. Research done in the Georgia Piedmont on the closely related E. cirrigera, indicate that 65% of nests found were under cobbles (2.5 to 30 cm), 16% were under boulders (greater that 30 cm), and 19% were under slate tiles (30x30x1 cm), which were added to the stream experimentally. To deposit eggs on the under surface of a rock, the female must flip on her back to make cloacal contact with the substrate. Three minutes is required to lay each egg in this manner, and up to several hours to lay an entire clutch. The eggs, when freshly laid appear white or pale yellowish, and each egg is 2.5–3 mm in diameter and is surrounded by two distinct membranes. Communal nesting in northern two-lined salamanders has been documented on several occasions and localities; New York, in Ontario, and likely in Ohio. Larval ecology Upon hatching, the gilled larvae are about 10 mm long, and remain in slow-moving pools, or less frequently, hiding in crevices between rocks and boulders in swift-flowing streams. The larvae do not begin feeding until their yolk sacs are reabsorbed, at which point they begin to feed on benthic invertebrates by prowling the bottom of the stream. Typical prey items for northern two-lined salamander larvae include chironomid larvae and other dipteran larvae, stonefly larvae, cladocera, and copepods. Predators of