Abstract: The external morphology of the compound eye of Chrysopa pallens Ramber and its microstructure under light and dark adaptation were observed by using scanning electron microscope and optics microscope. The results indicated that the compound eye with a shape of half sphere, located on the lateral upsides of its head, was composed of 3 600 ommatidia in both sexes. The angle between the foremost and the hindmost ommatidia along the axis was 180°, and the angle between the uppermost and the lowermost one was about 200°. Each ommatidium contained corneal lens, crystalline cone, 6 to 8 retinula cells and basement membrane where the pigment granules could be observed, which were encompassed by two primary iris pigment cells and six secondary iris pigment cells in periphery. In dark adaptation, the crystalline cone opened obviously, the distal retinula cell nucleus moved close to the crystalline cone, and the pigment granules of secondary iris pigment cells surrounded the crystalline cone. In light adaptation, the crystalline cone closed or opened slightly, both the distal retinula cell nucleus and most of pigment granules of secondary iris pigment cells moved to the proximal end and surrounded retinula cell column. No differences in the microstructure of compound eye were observed between male and female under the same light-or dark-adaptation, respectively. It was so concluded that the organization of the compound eye of C. pallens belonged to the type of superposition eye with a clear zone, which was characterized by the crystalline cone closing or opening, the longitudinal movement of distal retinula cell nucleus and pigment granules on basement membrane as well as the longitudinal movement of secondary iris pigment granules.

Key words: Chrysopa pallens, compound eye, ommatidia, external morphology, microstructure