94 AN INSECT NAVVY 



4 When the larva is full grown it forms a 

 globular cocoon by fastening together grains of 

 sand with fine silk from a slender spinneret 

 placed at the posterior extremity of the body. 

 In this cocoon it changes to an imago of very 

 elongate form, and does not emerge until its 

 metamorphosis is quite completed, the skin of 

 the pupa being, when the insect emerges, left 

 behind in the cocoon. We have no Ant-lions 

 inhabiting Great Britain, though specimens 

 introduced do very well in confinement.' 



The famous naturalist Keaumur gives us an 

 interesting account of the creature's habits : 

 1 The larvae are predaceous, and secure their 

 prey by means of pitfalls they excavate in the 

 earth, and at the bottom of which they bury 

 themselves, leaving only their elongated jaws 

 projecting out of the sand at the bottom of 

 the pit. It is a very unusual circumstance in 

 insect life that the larva of the Ant-lion can 

 only move backwards. In forming their pit 

 they use their broad bodies as ploughs, and 

 throw out the sand by placing it on their 

 heads and then sending it to a distance by a 



