Scanning Electron Microscope Studies of Steinernema Glaseri (Nematoda: Steinernematidae) 1

Scanning electron micrographs are presented of Steinernema glaseri. The male head of S. glaseri is slightly swollen and bears six labial and four large cephalic papillae. There are 11 pairs of genital papillae plus a single papilla. The spicule is unique with a short head, distinct shaft, long and narrow blade, and a spicule tip which has a ventral aperture and appears hook-like. A velum was not observed. The gubernaculum is much shorter than the spicule, with the anterior end curved ventrally, and enlarged gradually posteriorly. Usually, the capitulum and cuneus are forked anteriorly to form a Y-shaped structure. The female head has six labial and four cephalic papillae, and the vulva may be with or without a thickened flap. The lateral field pattern of the infective juvenile begins anteriorly with one incisure which after a short distance becomes three, six, seven and nine incisures which create two, five, six and eight ridges, respectively. At about the level of the phasmids, the number of ridges gradually decreases to two broad ridges.