8 



these circumstances, it lias to be remembered that its body 

 is very short and thick. It seems certain, therefore, that any 

 active bending of the body would have to take place in the 

 middle so as to form a semi-circular shape which, in fact, the 

 larva does take in later stages of the growth. In these 

 earliest stages, while the larva is still practically restricted to 

 the narrow confines of the egg shell, there is no room for such 

 a bending process. Moreover, as the legs are atrophied, they 

 cannot function in gripping the surface of the seed. The 

 posterior end of the egg is also narrow and is fully occupied 

 by the abdomen of the larva. 



The procedure which the larva follows in boring into the 

 seed is therefore very different from what one might expect. 

 The forces exerted in the process of boring into the seed 

 seem to be of two kinds. Firstly, the chitinous process being 

 fixed against the egg shell in the region of its greatest con- 

 vexity, forms a firm base for the action of the mandibular 

 muscles. Secondly, there is a thrust forward from the abdo- 

 minal end which, as already stated, is closely applied to the 

 egg shell. This forward movement is, by reason of the 

 attachment of the H-shaped process to the egg shell, con- 

 verted into a vertical force thrusting the mandibles against 

 the surface of the seed. 



As the larva is working, the chitinous process sways for- 

 ward and backward with the teeth as fulcra, and the lower 

 limbs of the H expand and contract as the head is pushed 

 downward out of the hood or withdrawn. When the sides 

 of the hole have to be excavated, the larva turns a little to 

 the right or to the left. In the process of turning from one 

 side to the other, the larva may turn completely over. The 

 meal excavated is worked back to the pointed end of the egg 

 by a peristaltic movement of the ventral surface. A little 

 is also worked on the sides of the egg shell . When the hole 

 is sufficiently large, the head with the chitinous process 

 closely pressed against the first segment is first inserted. For 

 obvious reasons the operations inside cannot be followed, but 

 larvae which have penetrated thus far, when exposed, show a 

 much attenuated neck and a swollen abdomen into which 

 apparently the viscera have been pushed back. The ad- 

 vantages of a narrow neck in enabling the head to work all 

 round the hole with ease, are obvious. There are reasons to 

 believe from observations made on penetration by the 

 larvse of free living forms that the chitinous process is fixed 

 along the side of the hole during further excavations 

 deeper into the seed. From the above description it will 



