722 'Journal of Comparative Neurology and Psychology. 



through the chitin overlying the light receptor apparatus. I have 

 sectioned heads of the larvse and been enabled to study the histology 

 of the organs in Delafield hematoxylin stains. A median section 

 through one organ is shown in the accompanying Fig. 1. In this 

 particular section, the chitin overlying the area had been torn off by 

 the microtome knife, but in other sections, where, unfortunately, the 

 histological elements were not as well preserved as in the present one, 



'.**!©'-^.it 



Fig. 1. — a, section through an eye-spot of a larva of Teneirio molitor at 

 right angles to the surface of the body. 6, portion of chitin covering the eye- 

 spot of another section, in Avhich the chitin overlying this eye-spot was intact. 

 The canals running from the surface to the interior through the chitin are 

 characteristic of the chitin over the whole of the head and not of this part 

 of the body alone. 



the chitin was intact, and I have drawn in & a portion to show the 

 characteristic structure. As Cole remarks, there are no lenses formed 

 in the chitin over the ''eyes," nor is there any difference in the trans- 

 parency of the chitin in these regions from that over other parts of 

 the head. When the eyes are examined in the living animal, with a 

 hand-lens, it is seen that the chitin is as dense and as opaque to light 

 as in other parts of the body. This fact, with the condition of the 

 other elements of the eyes, indicates that the whole apparatus is 

 structurally an imperfect organ for the reception of light. 



