The study on the glial cells in the brain of 5-day-old cabbage butterfly (Peiris rapae L.) was performed to observe their ultrastructures and then classify them on the basis of the differences in morphological and ultrastructural characteristics. The brain-subesophageal complex was prefixed in 1% paraformaldehyde-1% glutaraldehyde mixture for 4hrs, post-fixed in 4% OsO$_4$ for 1hr and then embedded in araldite mixture. The thin sections of whole parts of brain were made, stained with uranyl acetate and lead citrate and examined by Hitachi 500, JEM 100B and Hitachi HS-7S ectron microscopes. The glial cells in the brain are classified into four types and each type is characterized respectively as follows: Type I glial cell: Observed in the perineurial cell layer, these relatively small glial cells possess many cytoplasmic processes which include a large number of mitochondria. The soma is 4.5∼6.5$mu extrm{m}$ length and is occupied mostly by a rounded nucleus about 3.5∼4.5$mu extrm{m}$ in diameter. The chromatin shows several randomly scattered dense patches. The cytoplasm is populated with free ribosomes which aggregate into polyribosomal configurations. It also contains several granular endoplasmic reticulum and filamentous or oval mitochondria. Type II glial cell: These are large glial cells located among the neuronal cell bodies of optic lobes. The elongated nucleus averages approximately 15∼20$mu extrm{m}$ in length. The chromatin occurs predominantly in dense patch form evenly in karyodlasm contains numerous free ribosomes and granular endoplasmic reticulum. Mitochondria are sometimes observed. Type III glial cell: Located among the neuronal cell bodies or between the neuronal cell body layer and meuropile, these glial cells show the diversities in size and shape. The glial cell bodies averages 4.5∼11.0$mu extrm{m}$ in length and the rounded, oval or elongated nuclei are approximately 3∼11$mu extrm{m}$ in length. The chromatin appears in dense as well as diffused form. The cytoplasm occpuies a small proportions of the soma and is rich in free ribosomes. Mitochondria are often observed. Type IV glial cell: Occured in the neuropile of brain, these cells possess very elongated or irregular nucleus about 6∼9$mu extrm{m}$ in length. The chromatin occurs in diffused as well as dense form. The cytoplasm contains numerous patches of granular endoplasmic reticulum. The mitochondria are few in number.