Fig. 69. — Larva of crane-fly. 



130 INJURIOUS AND USEFUL INSECTS 



in the act of dividing the food. At the hinder end of the 

 body are six short conical projections, and in the centre of 

 the space enclosed by them are two large spiracles, the only 

 efficient spiracles in the body. By microscopical examination, 



a row of minute dosed 

 spiracles can be made 

 out extending along 

 each side of the body. 

 The larva devours dead 

 vegetable matter, as the 

 contents of its alimentary 

 canal show. It is likely that it also gnaws the roots of grass, 

 as it is well known that grass and corn are seriously injured by 

 the presence of a number of leather-jackets in the soil. 



When the larva has attained its full size, it casts the last 

 larval skin, and is converted into a pupa. The pupa, as 

 soon as it becomes free, takes a vertical position, and forces 

 its body through the soil to the surface, where it 

 sticks out about half of its body. In making its 

 way to the surface, it relies mainly upon a number 

 of short hooks, which project from all the segments 

 of the abdomen, and are particularly numerous 

 towards its extremity. The wings and legs of the 

 fly, as well as the head with its compound eyes, 

 can now be easily distinguished, though all these 

 parts are still enclosed within the pupal skin. The 

 legs and wings are much crumpled, and arranged 

 upon the ventral side of the body ; each is en- 

 closed in its own sheath. Just behind the head 

 there stand out from the dorsal surface of the 

 prothorax a pair of curved horns which lead into 

 the tracheal system, and constitute the respiratory 

 trumpets of the pupa. The position adopted by 

 the insect in this stage renders it an easy matter 

 to take in a fresh supply of air through the res- 

 piratory trumpets. After a few days the pupal 

 skin cracks along the exact middle of the dorsal 

 surface of the thorax, and through the fissure 

 the fly escapes, leaving the empty pupa-case sticking out of 

 the earth. 

 The crane-fly in its final stage is at once distinguished 



Fig. 70. 

 Pupa of crane- 

 fly, enlarged. 



