﻿THE ENTONOLOCilCAL MAGAZINE, Vo に II に Pt. Ill & VI. 119 



paratively large, by use of the dorsal eyes, and to search for victims, 

 comparatively small, by use of the ventral eyes. 



3. There are three kinds of pigment cells belonging to each omma ； 

 principal accessory and retina pigment cells. The last once are so 

 small that may often be overlooked, but are markedly large in the 

 nymphal eyes (fig. 4)' 



4. Principal pigment cells grow narrower towards the corneal 

 lens, along the wall of the crystalline cone, and their distal 

 extremities are scarcely extended between these two structures as 

 Zimmermann regards. I can not find any space left between the 

 cornea and the crystalline cone so far as observed in the celloidin 

 preparations, in which least heating is applied and on shrinkage of 

 structure is produced. The distal surface of the cone contacts with 

 the proximal furface of the corneal lens in its entire breadth. On 

 the codtrary in paraffin sections I frequently met with such cases 

 where a large space remains between the corneal lens and the 

 crystalline cone as he figures. 



5. Spaces left between every two crystalline cones are occupied by 

 three kinds of cells ； both principal and accessory pigment cells and 

 hypodermal epithelial cells. The first closely envelope crystalline 

 cones, the second enclose the first from outside, and the third fill 

 the most distal narrowest portion of the space (fig. 3)' Zimmermann 

 is the first author who reports the occurrence of accessory pigment 

 cells in two layers in dragonflies. One of these layers, however, 

 evidently corresponds to the hypodermal epithelial cells, not repre- 

 sents pigment cells. Not only we can trace, without interruption, 

 these cells up to the hypodermis underneath the chitin of extraocular 

 portion but also we can not discover any trace of pigment granules. 



6. These hypodermal epithelial cells are very long spindle-shaped 

 (fig, 3, 4, 5， h)， much resemble smooth muscle fibers, with a nucleus 

 ill the middle thickest part. With one end they attach to the 

 peripheries of corneal facets, and with the other end to tracheal sacs 

 mentioned below. 



7. Muscle fibers or fibrils with stripes as Vigier describes are found 



