INSECTS. 



191 



but this is all appearance, for this mask is in reality a wonderful apparatus 

 for seizing its prey. Some luckless insect or worm ventures near, when 

 the mask is suddenly extended as shown in the lower figure on the left, 

 and then the two jaws at its extremity grasp the prey. Now the mask folds 

 up again, bringing the object caught exactly under the mouth, where the 

 true jaws soon tear it to pieces of a suitable size for swallowing. The larva 

 does not depend on its legs alone for locomotion ; it has at the posterior 

 end of its body a curious syringe-like apparatus. Into this the water is 

 drawn, and then it is forcibly expelled, shooting the animal forward with 

 considerable force. 



The pupa differs from the larva in but little, except in the larger 

 wing-pads ; it continues the same predatory life, and no one who has not 

 studied them can have any idea of the amount of life they destroy. By 

 and by the time comes when the pupa is to change to the adult. It 

 climbs up some plant to the surface, and then the skin of the back splits 

 open, and from the opening emerges the perfect dragon-fly, perfect in all 

 except that its wings and body are soft and flabby. A short exposure 

 dries its wings, and then away it flies. The whole of these changes 

 have been described by Tennyson in his " Two Voices " : — 



" To-day I saw the dragon-fly 

 Come from the wells where he did lie. 

 An inner impulse rent the veil 

 Of his old husk ; from head to tail 

 Came out clear plates of sapphire mail. 



" He dried his wings ; like gauze they grew ; 

 Through crofts and pastures wet with dew 

 A living flash of light he flew." 



In early summer the water gives birth to other forms besides the 

 dragon-flies, and among them to may-flies; insects with large front wings 

 and small hind ones, and the body terminating in two or three long tails. 

 The name may-flies is given from the fact that many of 

 them appear in the month of May. while another name, 

 day-flies, alludes to the short duration of their life as per- 

 fect insects, sometimes lasting but a few hours. They 

 leave the water in the night, and in some places — for in- 

 stance, Buffalo — in such numbers that they sometimes 

 obscure the street-lamps. In their brief existence they 

 lay their eggs in the water, and that is all. The larval 

 stage is much longer, in all lasting for nearly a year, fig.176.— May-fly (Po- 

 and in some forms for two or three years. *«*)■ 



