Photo: J. J. Ward. 



FOOT OF A HOUSE-FLY 



Showing two claws for gripping minute rough- 

 nesses and, between the claws, a double pad or 

 cushion which is used in climbing up a smooth sur- 

 face like a window-pane. The probability is that a 

 moist secretion from the pad helps the adhesion. 

 There is also very close apposition of the cushion to 

 the smooth surface, and some say a partial vacuum 

 is formed. But we are not quite sure how a fly 

 runs up a window-pane one of the most familiar 

 sights in the world. 



Photo: J. J. Ward. 



THE BEAUTIFUL PATTERN ON THE MICROSCOPIC FLINTY SHELL 



OF A DIATOM (Arachnoidiscus Ehrenbergi), A KIND OF r\i 



CELLULAR PLANT 



Two hundred of these cells placed side by side would scarcely extend one 

 inch. It is not known that there is any utility in these beautiful markings. 

 They are expressions of rhythmic orderly growth^ 



