A technique for establishing microplots in the field.

the lateral field. The basal layer, averaging 0.5 /~m in thickness, has vertical striations with a periodicity of approx. 0.025 /~m. At the edges of the lateral field this layer becomes forked and is replaced, under the field, by two obliquely oriented fiber layers (Fig. 3), each of which appears to be composed of many fibrils. A thin, often discontinous electron-transparent zone separates the striated basal layer from the underlying hypodermis. Beneath the cuticle is a membranebound hypodermis and basal lamella similar to that reported for M. incognita by Baldwin and Hirschmann (1). The observations reported here for M. hapla males are in agreement with those of Bird (2) and Baldwin and Hirschmann (1) for M. iavanica and M. incognita, respectively. The cortex could be resolved into the same five layers as observed by Baldwin and Hirschmann (1) in M. incognita. The author (unpublished data) has also observed these five layers in the cuticle of M. javanica males. The cuticle structure of M. arenaria (Neal) Chitwood males is also similar (Johnson, unpublished data). I t appears Ultrastructure of M. hapla: Johnson 233