Marvels of the Universe 



dexterous hands, set just 

 under the mouth. More- 

 over, their labours are ably 

 supplemented by the lower 

 lip, an organ which really 

 represents a third pair of 

 jaws intimately fused to- 

 gether. All these mouth- 

 parts work in unison with 

 amazing precision and ad- 

 dress. 



I will now ask the reader 

 to glance for a moment 

 through a microscope at 

 the Diving Beetle's eye. 



185 



Photo 60] \_H<i<jh Main. 



\^*hen the Grub is about to change into 

 a chrysalis it constructs a rude celi at the 

 margin of the pond, vtrhere — 



The surface of this amazing 

 sense-organ consists literally 

 of thousands of facets. 

 That each of these facets 



l*hoto /))/] 



it lies quietly for a few days, 

 out of its last grub suit — 



is a perfect lens may be readily perceived by looking through a magnified eye at some object, such 

 as a postage-stamp. Every facet forms a tiny image of the stamp, and on page 187 we give a 

 photograph of a single stamp with part of the beetle's eye used as the camera lens, the result 

 being that the stamp is greatly multiplied in the photograph. That the beetle actually sees all the 

 images is hardly probable. We must remember that each of our own two eyes produces an image, 

 while only one picture is registered \>y the brain. The most plausible explanation of how the beetle 

 really sees wth its compound eyes was suggested by Johannes Miiller early in the last century. 

 The gist of his theorj' is that the beetle perceives with each facet not a complete image, but a tiny 

 section thereof, and that these sections are pieced together to form one mosaic picture. Thus we 

 must assume that the Diving Beetle sees only one image of an object at which it is gazing, but because 



its faceted eyes cover a large 



area of its head we may be- 

 lieve that the insect enjoys 



quite a panoramic outlook — 



seeing simultaneously to right 



and left as well as above 



and below. 



So much for the physical 



equipment of the adult 



Diving Beetle. Let us now 



sketch briefly its life- story. 



The mother beetle makes 



incisions in the submerged 



stems of rushes or pond weeds 



with her sharp egg-tube, and 



inserts her white, slightly 



curved eggs. She acts thus, 

 phoiohy-\ yiu'jh Main. ^q^ because her youngsters 



and is transformed into a white mummy- .^jj^ f^^^ ^ ^J^g Vegetable 



like creature, very diftcrenl rrom the per- ^ '-' 



feet inaect. but— substancc, but as a precaution 



\_lluijlt AfaJn. 



I'ltuto hi/l 



careful examination will show the several 

 parts of the future Beetle pacUed closely 

 together in this strange shroud. 



