LAZY-TONGS, 455 



an invalid, and seize the required object by the tongs at the 

 further end. 



The only drawback to its use is, that the instrument cannot 

 be shortened without opening the tongs. But, if some plan 

 could be devised whereby the tongs could retain their hold 

 under those conditions, the instrument would be a perfect one. 



Exactly such a Lazy- tongs we have in Nature, in the well- 

 known "mask of the larva and pupa of the Dragon-fly. 5 ' It 

 is called a mask because, when closed, it covers the face. 



It chiefly consists of two flat, horny plates, hinged in each 

 other like a carpenter's two-foot rule, and being capable of 

 extension to a considerable length. The end is widened, and 



PBOB03CIS OF HOUSE-FLY. MASK OF DBAGON-FLY LARVA. LAZY-TONGS. 



furnished with two jaws, which take the part of the tongs in the 

 instrument above described. 



This curious apparatus is used for the purpose of securing 

 prey. 



I have kept many of these creatures, and watched their mode 

 of feeding. As has already been mentioned, they have two 

 modes of progression, i.e. walking by means of legs like those 

 of ordinary insects ; and driving themselves along by ejecting 

 water from the tail, on the principle of the rocket. As far as 

 I have seen, the latter mode is always used in taking prey. 

 The Dragon-fly larva always lives at the bottom of the water, 

 though it can force itself to the surface if needful. And, like 

 the dreaded ground-shark, it seizes its prey from beneath. 



Its favourite food is the larva of the whirlwig-beetle, a 

 fat white grub, with a number of white, soft, feathery gills 

 fringing its sides. In order to produce a current of air over 

 these gills, the larva wriggles itself up to a height of severaj 



