646 William Patten 



cognìzed, iu the larvai, than in the adult condition. These two facts 

 indicate that the cuticular hypodermìs must have once constitiited a 

 more important and conspicuous part of the eye than at present. 



Mautis religiosa. 



The thick cuticular coveriug of the eye is divided into hexag-onal, 

 hiconvex facets, the inner surface being more strongly arched than 

 the outer. They are divided into a hard, homogeneous, outer layer 

 (fìg. llSc'), and a thicker. less refractive, inner one, composed of agreat 

 mimber of thin , superimposed layers having the same curves as the 

 outer surfaces of the facets. The latter are separated from each other 

 by a thin layer of chitinous substance, the refractive index of Avhich is 

 different from that of the facets (fig. 1 IS). On the periphery of the inner 

 surface of the latter, are two small nuclei e.h., around each of which is a 

 rather large, triangulär space, filled with protoplasm, diminishing quite 

 rapidly in thickness towards the centre of the corresponding facet. I 

 have only been able to study these nuclei in sections, since the fresh 

 material at my command was not suftìcient for maceration. It is only 

 by the latter method, by which one may isolate large portions of the 

 cornea! cuticula with their underl3'ing nuclei, that an adequate knowl- 

 edge can be obtained of the number and arrangement of these cells, 

 to which the corneal facets owe their origiu , and which form a con- 

 tinuous and distinct layer, — the corneal hypodermis, — between 

 the cuticula and the ommateum. The latter is composed of a number 

 of ommatidia, each one of which, in turn, cousists of four centrai 

 r etino phorae surrounded by several rows of pigment cells. The outer 

 euds of the retinophorae are greatly enlarged to form the calyx, 

 which contains the retin idi um. The two inner thirds are reduced to 

 a narrow tube, the st} le, which nearly corresponds with the so- 

 called rhabdom of Grenacher. 



The calyx is surrounded by a layer of yellowish browu pigment 

 cells, the nuclei of which are so arranged that it is difficult to determine 

 their number, but they appear to form two, rather indistinct rows. In 

 longitudiual sections, it is only occasionally that one sees isolated, ovai 

 nuclei high up, between the retinophorae, as in fig. 118, jt?^'. But in the 

 large space, formed by the constriction of the inner ends of the calyees 

 are several large nuclei, varying considerably in size, and undoubtedly 

 belonging to the yellowish brown pigment cells. These cells do not 

 show any distinct constrictions, and it is therefore difficult to determine 



