398 NATURE'S TEACHINGS. 



twig, and upon it deposits a little drop of a slimy consistence. 

 She then draws out this drop into a thread, which hardens as it 

 is brought into contact with the air. At the extreme end of 

 the thread she places an egg, which is thus kept at some height 

 above the ground, and defies the approach of inimical insects. 

 The eggs, as well as the stalks, are perfectly white, and have 

 so singular a resemblance to mosses, that for many years they 

 were actually classed and figured as such. 



These egg-groups are plentiful enough, if the observer only 

 knows where to look for them. I have several of them in my 

 collection, and have found that nearly every one who sees them 

 for the first time takes them for mosses. I never myself saw 

 the pretty insect lay its eggs, and for the description am 

 indebted to Mr. A. G. Butler, of the British Museum, who has 

 kept them and watched their habits. 



The objects on either side of the Lace- wing Fly's eggs are 

 egg-groups of certain spiders, suspended by threads from 

 branches. 



A STILL more remarkable instance of unconscious imitation 

 may be found in the two objects in the accompanying illustra- 

 tion. It is hardly necessary to say that the right-hand figure 

 represents a portion of the arrangement by which a butcher 

 hangs up his meat out of harm's way until it is wanted. 



The hooks in question are simply formed into a double curve, 

 like the letter S, and can be slid along the horizontal bar with- 

 out any danger of falling. 



Now, in the common Sloth we have an exact prototype of 

 the butcher's hook. The Sloth passes the whole of its life in 

 the remarkable attitude which is shown in the illustration. 

 It lives among the branches not on them, but under them 

 its claws being long and curved, just like a butcher's hook. 

 I have often watched the animal traversing the branches, and 

 have been greatly struck with the accurately picturesque 

 description of the late Mr. Waterton, who was the first to dis- 

 cover the real character of the Sloth. 



It was he who found out that the previous ideas as to the 

 Sloth's mode of life were utterly erroneous, and that, instead of 

 being a sort of bungle, the Sloth was as perfect in its way, and 

 as well fitted for its mode of life, as the lion or tiger. He dis- 



