ioo THE CRANE FLY 



vertebrate animal, and are seated on very large 

 special lobes of the brain. These lobes, indeed, 

 are so large and so complex in structure that 

 the insects may be described as possessing 

 special ocular brains brought into relation with 

 the lights, shades, and movements of the ex- 

 ternal world by a remarkably complex optical 

 apparatus. 



The illustration is taken from a photo-micro- 

 graph representing a portion of the insect as 

 if amplified to 35 diameters. It is the result 

 of one minute's exposure to gas-light. The 

 focal distance was 70 inches, and the objective 

 used was the 2-inch. 



Antenna of Melolontha. 



This object, one of the antennae of the 

 cockchafer, is well adapted for photographic 

 purposes, and can even be sketched in outline 

 with great ease by using the camera lucida. 



Throughout the whole surface of this com- 

 pound appendage an enormous number of 

 small circular cavities is observable. If 



