Abstract
The developmental process of the compound eye in Maladela castanea was observed. The third instar larvae of this insect collected from the field were reared at a constant temperature of 25°C, and used succeedingly as the material of larvae, pupae and adults. The compound eye is formed by differentiation of the hypodermis situated at the anterior part of the lateral ocelli of the larva. The larval ocelli are withdrown inward with the approach to pupation. The cornea which appears originally as a thin membrane becomes suddenly thicker during 9 to 10 days after pupation. The crystalline cone cells seem to have been concerned with the formation of the cornea. The four crystalline cone cells begin to secrete cone forming substance as soon as pupated, and the four cone units fused each other into a lump of cone four days after pupation. However, the adult-type crystalline cone is accomplished more than one day after emergence. The retinula is composed of eight cells, one nucleus among them is situated at the proximal area of the ommatidium throughout the development. There are two iris cells containing the pigment granules abundantly. In early stage their nuclei are distributed at the distal part of the crystalline cone cells, but later move proximally with the progress of development. The retinular pigment cells are six in number. Their nuclei are early located near the basement membrane, but afterward move distally until they reach a slight distal level of the nuclei of retinular sense cells after more than 24hr from emergence. Then the development of the compound eye is accomplished.
